Education Standards

Human Reproduction- The Basics, 9-12 Lesson 1

Human Reproduction- The Basics, 9-12 Lesson 1


This first lesson (of three) explains sexual and reproductive anatomy, and human reproduction via penis-in-vagina sexual intercourse (PIV sex). During this lesson, the educator will model the use of respectful, inclusive concepts and language to describe the process of human reproduction and family formation.

Human Reproduction- The Basics, HS Lesson 1

Lesson Description

Grade Level

High School

Suggested Time

60 minutes with a 15 minute optional supplement


Rachel Ginocchio, MPH, Roads to Family

In collaboration with:

Gaye Chapman, Portland Public Schools

Nora Gelperin, MEd, Advocates for Youth

Danni/y Rosen, Co-Chair, GLSEN Oregon

In consultation with:

Yesenia K. Char

Yena Perice

Madelyn Mae Rocamora Belden

Jacqueline Singer

Black Student Union (BSU), Cleveland High School

Cleveland Alliance for Racial Equity Leadership (C.A.R.E.)

Cleveland High School and Leodis V McDaniel High School health students

Cleveland LatinX Student Union

Paula Amato, MD, Professor of Obstetrics and Gynecology, Oregon Health & Sciences University

Andy Dettinger, ODHS Youth Services, My Future-My Choice

Jacqueline DiBernardo, Writer, RKW Creative

Mariotta Gary-Smith, MPH, Certified Sexuality Educator

Amy Penkin, MSW, LCSW, Clinical Program Manager, Transgender Health Program, Oregon Health & Sciences University

Ann Scott, MD, FACOG, Doctor of Obstetrics and Gynecology

Jess Venable-Novak, Family Equality

Oregon Sex Education Steering Committee

Oregon Sexual Assault Task Force's (SATF’s) Abuse Prevention Learning Collaborative

Oregon Youth Sexual Health Partnership (OYSHP)

Anatomy Illustrations by:

Mel Latthitham, Graphic Designer, Sweet Bonny

Essential Questions Covered

How do most human human bodies work to create a pregnancy through penis-in-vagina sexual intercourse (PIV sex)?

When educators teach only one means of human reproduction (PIV sex), and that's all that people understand, who is included and who is left out? What messages does this convey?

What are some examples of inclusive concepts or language we can use when explaining human reproduction? Why is an inclusive approach important?

Culturally Responsive Practices

The three lessons in this series are about equity, diversity, and inclusion, around human reproduction and family formation. So often, students and their families who are here thanks to assisted reproduction, or who join their family through adoption and foster care are left out of the typical narrative. By teaching the concepts in these lessons, educators will include every student in their class and all of their family structures in the explanation of human reproduction, equally. Throughout the lessons, students are invited to share, explore, and celebrate their large funds of intersectional knowledge (all shaped by their identities, genetics, and experiences) around how they came into the world and what family/kinship/community means to them.

We do want to acknowledge that although the creation of these lessons was driven by the experiences and ideas of students and professionals of various intersecting identities, they are largely written from a western perspective/cultural standpoint.

Lesson 1 Objectives:

  • Understand how reproductive anatomy works to create a pregnancy.

  • Identify 6 steps necessary to start a pregnancy with penis-in-vagina sexual intercourse (PIV sex).

  • Learn new concepts and an inclusive language to explain human reproduction and family formation.

Information for Educators

The following information will be repeated in each of the three lessons:

The three lessons in this series expand the typical explanation of anatomy and reproduction to be inclusive of every student and every family structure. We discuss penis-in-vagina sexual intercourse, insemination, and IVF. In this way, all students can see themselves in the lessons on human reproduction and family formation. This includes students who are donor conceived (egg, sperm, and embryo donation), those gestated and birthed via surrogacy, and those who come to their families through adoption, foster care, remarriage, and many other avenues.

This first lesson focuses on fertilization through penis-in-vagina sexual intercourse (PIV sex). The second lesson introduces insemination, in vitro fertilization, donors, and surrogates. The third lesson pulls together all of the concepts introduced in the first two lessons.  

In the second lesson, students will apply their knowledge of how PIV sex works to create a pregnancy to explain insemination and IVF. They’ll then take their understanding further, by learning how people other than parents, such as donors and surrogates, play a role in human reproduction and family formation. The activities will be done in small groups, where students can help each other understand the concepts and where they can practice using an inclusive approach to human reproduction, which the educator modeled in the first lesson.

In the third lesson, students will work in small groups, researching celebrity families. This activity will enable them to pull together all the concepts they learned in the previous two lessons, and to demonstrate their progress in understanding the material.

These lessons are designed with formative assessment questions built in. The educator can speed up or slow down the material, depending on where students are in their understanding and interest in the material and how much class time is allotted to these lessons.

The three lessons in this series are designed to be taught consecutively. However, since teaching time is short, the following are suggestions for modifying the length of these lessons:

  • If students already have a strong foundational understanding of human reproduction through PIV sex, educators can skip Lesson 1.
  • Lesson 3 is a hands-on activity that enables students to apply the knowledge they gained in Lesson 1 and 2, and helps educators assess student understanding. This lesson can be skipped or assigned as homework.
  • If students already have a basic understanding of all means of reproduction (PIV sex,  insemination and IVF), they can dive right into Lessson 3, where they can apply their knowledge and demonstrate their understanding.
  • Depending on students’ level of proficiency, there are sections within the lessons that can be skipped or elaborated on. We have noted these in the lessons.
  • We have kept the slides for these three lessons in one slide deck. We hope this helps teachers pace the material according to students’ proficiency and how much time they have in their class period. When class periods allow for more content, educators can simply skip the wrap-up activities at the end of one lesson and move onto the next.

Suggestions for scope and sequencing:

Our lessons fit well after students have a basic understanding of puberty, the difference between sex (female, male, and intersex) and gender, sexual orienation, consent, health equity/disparaties and media literacy, and before contraception and STI prevention. For resources on these topics, please see “Links for Supplemental Materials” at the end of this lesson.

All the materials created for these lessons begin with RTF, which stands for Roads to Family. We hope the RTF designation helps you keep organized with all the available resources.

In addition to the three lessons on human reproduction, Mariotta Gary-Smith has also written two additional lessons which guide the students in their exploration of family, kinship and community. We highly recommend these lessons either before or after this series. These lessons begin with the letters MGS.

Please keep in mind that although you (as the educator) might be unfamiliar with some of the material in these lessons, many students in class are here thanks to assisted reproduction, including donor conception and surrogacy. Some of these students have been explaining assisted reproduction to their peers since they were in elementary school. They may be willing to share their funds of knowledge and expertise, but it may also be a relief for them not to be the one explaining things. When assisted reproduction is part of mainstream education it destigmatizes and normalizes everyone’s experience!

We have chosen to use the term PIV sex, to represent penis-in-vagina sexual intercourse, since this is the type of sexual intercourse than can lead to a pregnancy. Others use sexual intercourse or vaginal intercourse. There is no one right term to use, so use the vocabulary that is best for your community, and feel free to change the slides and handouts accordingly. Just be sure to clearly define the terms you use.

If any of the words in the lessons cause you to feel uncomfortable, it can be helpful to practice them out loud several times, in the privacy of your own home, before introducing the concepts to the class.

Please know your state and district policies regarding what you can and can not teach in regards to comprehensive sexuality education.

Links and Materials for the Lesson

Media Links

Educator Materials

Before the lesson, please read:

For the Lesson

  • For small group activities, students can work with peers at their tables, or the educator can pre-assign groups.
  • The slides for this lesson: Slides - Human Reproduction, The Basics
  • The handouts for this lesson:
  • Three large sheets of paper taped to the wall (need markers), or on a designated space on the whiteboard (need dry erase markers) that can remain for the duration of the three lessons. At the top of each sheet, write:
  • “Group Agreements”
  • “Parking Lot”
  • “Word Wall”
  • Computer, LCD projector, screen, and speakers to broadcast sound from videos.
  • A watch, clock or stopwatch for keeping track of time
  • Anonymous question box and a stack of small papers, uniform in color and size to maintain student anonymity, or an online tool for students to submit anonymous (e.g., Padlet, Pear Deck, Menti, etc.).

Student Materials

At each table group and for the scribe:

Table groups will also need (place in center of table):

  • Paper and pen/pencil or markers
  • Paper for anonymous question box


Lesson Overview

Before the Lesson

Gather all educator and student materials. Set-up classroom for small group activities.

Slide 1: Title Slide

Note to Educator: The title slide can be up when students come into class.

Note to Educator: To follow is a suggested narrative for you to use with your class. Please modify so that you use the language and concepts most appropriate for your community, and that which meets your district and/or state policies, which may dictate what you can and can not discuss. We have indented and italicized notes to you that are not part of the narrative, we have highlighted media links in blue, and questions to ask the student in green.

During the Lesson

Climate Setting (7 minutes)

Slide 2: The zones

Growth Zone

For the next three lessons, we are going to be talking about human reproduction and different family arrangements like nuclear, adoptive, and chosen families. I know that these can be very personal topics for some people. But, our goal is to remain in the growth zone. Being in the growth zone means we are sharing new ideas, stretching our understanding, and honing new skills. Being in the growth zone can often be uncomfortable, but is tolerable.

However, if the lessons are causing you to feel overwhelmed or unsafe, you have likely entered the panic zone. If this is the case, I urge you to take care of yourself. You can . . .

Note to educator: You can modify this slide to include your district and/or classroom protocols. If you don’t have specific guidelines, you can make some suggestions like breathing exercises, stepping outside of the classroom or getting a sip of water.

Group Agreements

Note to Educator: Remind students that whatever agreements are already in place for a successful learning environment apply to this unit on human reproduction. If your class has not yet written group agreements please see the list of resources for guidance. Write agreements on a dry erase board or newsprint that can remain throughout the duration of these three lessons - you’ll want to be able to refer back to them.


  • If students don’t bring up “embrace awkwardness” as a group agreement, you can offer it and get their response.
  • If students suggest that the classroom be a “safe space” ask students how they feel about using the words “brave space” instead, to encourage students who are feeling unsafe but who are willing to stay and participate.Be sure to mention that if any of the classroom activities are painful or hurtful to a student, they have the right not to engage and that you welcome hearing about an alternative activity they’d like to do instead.

Parking Lot

Because this is the first time I am teaching this course, you may have questions that your fellow students can’t answer, or that I can’t answer. We’ll write them on this Parking Lot and at the end of class I’ll ask for volunteers who are willing to do a little research and bring back answers for our next lesson.

Note to educator: Modify this narrative, depending on your comfort level with the material.

Class Scribe

As we go through the lessons we will build a word wall where we define new concepts. Who would like to be our class scribe today? As new words come up, your job will be to add the words and definitions to our word wall.

Note to educator:

If no student volunteers, the educator can be the class scribe. As students see what is entailed, they may be more willing to take on the role. Periodically check in to see if anyone is willing.


Assign one student by handing them the marker/dry erase. After they write their first word and definition, they get to pass the ‘baton’ (the marker/dry erase) to another student of their choosing.


If students have access to computers during class, you can build an anonymous word wall in PearDeck, Padlet or Menti, and students can all add to the definitions or comment on one another’s definitions. This also serves as a formative assessment tool, to see where students are in their understanding.

If a student takes on the job, you can give them the handouts:

  • Family Vocabulary
  • Reproduction Vocabulary

Introduction (5 minutes)

Slide 3: Overview

Over the course of three lessons, we are going to explore all the ways humans reproduce and form a family. For some of you, the concepts will be familiar, which is great — I invite you to share your knowledge and experiences with the class if that is something you are comfortable doing. For others, a lot of the material will be new.

There are many different definitions of the word sex. Since this lesson focuses on the type of sex that can lead to a pregnancy, I am going to use the term penis-in-vagina sexual intercourse, which I will be calling PIV sex for short.

Although today’s lesson is designed as a review of PIV sex, we can spend as much time on the material as we need.

Lesson 2 introduces the concepts of assisted reproduction — when our bodies need help to begin a pregnancy. We’ll be talking about insemination and in vitro fertilization and the role of egg, sperm and embryo donors, and surrogates. It’s okay if you don’t know what these words mean, we’re going to go over all of them in detail. The main point is that there are lots of ways to reproduce, which also means that there are lots of ways to form family.

For Lesson 3, you will be working in groups to research how famous families formed and then present your findings.

What is just as important as understanding new concepts, is learning and practicing using inclusive, affirming language to describe different kinds of families and the process of human reproduction. Our goal is to do so without gendering body parts, or making assumptions about people’s sexual orientation or gender identity, and by including all the different people who can play a role in conceiving, birthing, and caring for children.

Your job today is to listen and ask questions, and see how this approach sits with you. During Lesson 2, you’ll get a chance to practice using the new words on the word wall. In Lesson 3 you’ll have an opportunity to demonstrate your knowledge and understanding.

In the end, I hope these lessons help you better understand how you were brought into this world and how your friends and family members came to be. I also hope you will see all the possibilities for your own future, if reproduction is something you’re interested in. If you’re not interested in having offspring in the future, we hope this information encourages you to support your friends and other people in your community. Ultimately, I hope an expanded vocabulary and understanding enables you to communicate more inclusively and respectfully about all the ways humans reproduce and forge families.

Note to Educator: Have scribe write these words on the word wall, insemination, IVF, donors, surrogates. Remind the students that anytime a word comes up that needs defining, they can raise their hand to let the scribe know. The scribe can use the Word Wall handout to write a brief definition, or you can help them out with these simple definitions:

  • PIV sex: fertiliztion inside the body, without help
  • Insemination: fertilization inside the body, with help
  • IVF: fertilization outside the body, with help
  • Donors: people who give their cells to someone else so they can create a pregnancy
  • Surrogates: people who give birth to a baby for someone else

Student Inquiry: Any comments, feedback, or questions about what these lessons are about?

Slide 4: Today’s agenda

Here is our agenda for today.

After our warm up activity, we’ll talk about human reproductive systems and how they work to start a pregnancy through PIV sex. For this lesson, I will be introducing some new terms that I hope will make the discussion more inclusive of everyone in the classroom. At the end, we’ll talk about how the typical words we use to describe human reproduction leave people and families out of the conversation and can even be hurtful or stigmatizing.

Warm-Up Activity (10 minutes)

Student Inquiry: Anyone know the game Boggle? If so, can you describe it?

We are going to play a version of that with types of families. A type of family or a family structure is a way of describing the relationships in a household — like a single parent family or an adoptive family.

Grab a piece of paper and when I say go, you have 30 seconds to write a list of all the different types of families or family structures you know.

Note to Educator:  When time is up, ask for a volunteer to go first. They can read off the family arrangements they came up with. If any of the structures need clarification, have students define them for the rest of the class. If any other student has that particular arrangement on their list, they have to cross it off their list. When the first person is done reading their list, ask if anyone else has other kinds of family arrangements listed. Have them say theirs out loud. Again, if anyone has that same one, everyone who has it on their list has to cross it off. The student with the most structures left on their list wins!

  • If students are unwilling to share, the educator can modify the activity by reading some of the family structures listed on the Family Vocabulary handout.
  • This activity gives the educator an idea of how familiar students are with alternative family structures.
  • If students don’t mention the following families add: childfree families/families without children and chosen families.
  • Students may argue if one type of family structure is the same or not. E.g., one student might say single parent and other might say a single transgender parent. Students can quickly state their case, and the class can vote if the entries remain as different or if they need to be crossed off. It does not matter one way or another, but always err on the side of inclusion. The idea is to get them thinking and talking (and perhaps disagreeing) on the various definitions and types of families.

Slide 5: Quote

These days, less than half of US families are comprised of a married, heterosexual couple raising their genetically-related children.

So, less than half of today’s families are what we call a traditional nuclear family: mom, dad, married, PIV sex to bring kids into their family, kids all genetically related and looking alike!

Since there are many ways to be a family, there must be many ways to create babies. Like, for single parents and families with same sex partners — they perhaps didn’t make babies the traditional way, right?

Reproductive Systems in Action (30 minutes)

New technologies and medicine enable us to make new humans in all sorts of ways. Yet, no matter how we start a pregnancy, it takes the same three ingredients. 

Student Inquiry: Who can tell me what three things are needed to create a pregnancy?

Note to Educator: Students might say egg, sperm, penis, vagina, two people, a man and a woman, a relationship, etc.

Slide 6: Simple explanation of reproduction

Those are all good answers — they include anatomy, relationships and people! From a biological perspective, it takes an egg cell, a sperm cell and a uterus to make another human.

Student Inquiry: Anyone want to tell the class how an egg, sperm and uterus work together to create a pregnancy?

Note to Educator: One student can voice their ideas. Ask if any other students want to add to what the first student said. Welcome all answers whether brief or detailed. However, students may not want to answer, and that is okay. By asking you are showing them that discussing human reproduction is an acceptable thing to do.

When an egg and sperm cell join together through fertilization, they create an embryo. When an embryo implants in the uterus, it can continue to develop, or gestate, into a fetus. If development continues for about 9 months, a baby is usually ready to be born.

Seems like a pretty simple biological process, doesn’t it? But in reality, we are talking about bodies, people, relationships, expectations, hopes and a whole lot of other human stuff. In addition, when a baby emerges the baby needs to be taken care of. So when the humanness of making and raising children is mixed with the biology of reproduction, the explanation can get complicated. But, the complicated explanation of human reproduction is also much more interesting and inclusive.

But for now, if you remember nothing else from the next three lessons, this simple explanation gives you a vocabulary to talk about human reproduction in a way that applies to every human being on the face of this planet. It does not assume the gender or sexual orientation of the people involved. It does not define their relationship as loving, as in “mommy and daddy love each other very much.” It does not specify how many people are involved. It does not define family in any particular way.

For better or worse, I am going to label the sperm, egg and uterus as baby-making ingredients. I know that this labeling isn’t perfect, since not everyone will choose to reproduce, not everyone is biologically capable of reproducing, and most of the time these ingredients don’t result in a pregnancy or the birth of a child. However, we are all here because of these three ingredients and because this lesson is about reproduction, I felt like it is an okay label. We could also call them pregnancy ingredients or baby-making or pregnancy resources, materials, building-blocks, or something you come up with!

Student Inquiry: Thoughts, feelings, comments? Anyone have a different framework we could experiment with as we move forward?

Note to Educator: If students come up with a better language framework you can substitute that into the lesson or mention it as you move forward.

Head’s up — in order to talk about human reproduction, we are going to look at some illustrations of human reproductive anatomy. I know that looking at anatomy can be uncomfortable for some students. If you find this is the case for you, please do whatever you need in order to ground yourself — take a deep breath, scrunch your toes, count back from 10, or do whatever else helps you handle your discomfort in a productive way, so that we can move forward with the lesson.

Slide 7: Human anatomy

Note to Educator: Bring up illustrations and pause for a few seconds, so students that are uncomfortable can re-center themselves.

Note to Educator: If you have not covered the difference between sex assigned at birth (female, male and intersex) and gender, this is a good place to add it.

Everyone’s body is unique and nobody’s body looks like these stylized illustrations of just two types of reproductive systems. But I am going to use these two versions of the human body to demonstrate how reproductive systems can work to create a pregnancy.

Humans usually have an egg and baby transport system, or a sperm delivery network. They are located inside the body, below the belly button.

Both systems function the same way — they are a series of tubes and tunnels, designed to get egg cells or sperm cells from where they are made to where they need to go, to begin a pregnancy.

Our reproductive systems do other things as well, like provide sexual pleasure. The sperm transport system is also used for urinating. But today, we are focusing on their function in creating a pregnancy.

Since human reproductive systems transport egg and sperm cells, they also transport the DNA inside of those cells. As the lesson unfolds, you will see that sometimes people get their genetic code from people they regard as their parents and sometimes it comes from other people.

The body can only create a pregnancy after puberty has begun, so we are going to look at mature reproductive systems.

Let’s look at the baby-making ingredients in detail, in a mature body.

The Ingredients — Sperm Cells

Note to Educator: As you describe how sperm travel through the sperm transport system, you can use your finger, mouse, or laser pointer.

Slide 8: Sperm Transport

The sperm transport system is a series of tubes and tunnels designed to get sperm from where it is made to where it needs to go to start a pregnancy.

We are going to start with sperm cells. Another word for a sperm cell is a gamete.

Once puberty begins, the testes make and store millions of sperm. Sperm are the smallest cells in the body — you can only see them with a microscope.

After sperm are made in the testicles, they travel to the epididymis which is a tangle of nearby tubes. In the epididymis, sperm mature and develop the ability to swim on their own.

When sperm are ready to be sent on their way, they travel through tunnels called the vas deferens, where they pick up a grayish-white, liquid from the seminal vesicle and the prostate. The combination of the sperm and the liquid is called semen. Semen is ejaculated out the tip of the penis.

Although semen adds up to just a little over a half a teaspoon on average, it contains about 40 - 200 million sperm.

Note to Educator: If students ask, semen is made of sperm cells and fluid from the prostate which neutralizes the acidity of the vagina. Seminal fluid contains proteins, fat and sugar to nourish the sperm. There is also the cowper’s gland that secretes a fluid (pre-cum) to neutralize the acidity of the urethra to enable safe passage for sperm.

For ejaculation to happen, the penis is usually erect — which is when the penis stands stiffly away from the body. But erections can point up to the ceiling or down to the floor and everything in between. Regardless of the angle, someone’s penis is usually erect when it sends sperm out of the body.

Student Inquiry: Any questions, thoughts, or comments about how the sperm transportation system works?

What words should we add to the word wall?

The Ingredients — Eggs Cells

Slide 9: Egg transport

Now let’s talk about where egg cells come from. Another word for an egg cell is a gamete.

Note to Educator: If students ask, an egg cell is also called an oocyte. Once it matures it is called an ovum (ova is plural for ovum)

Unlike with sperm, puberty is not when eggs are made in the ovaries. Eggs are formed in the ovaries before a person is even born. In fact, by the time a person with ovaries is born, those ovaries likely have all of the eggs they will ever have — about 2 million.

Eggs are about the size of a dot at the end of an exclamation point! They are the largest cell in the body.

A couple years after puberty begins, most people with an egg and baby delivery system begin to ovulate and then menstruate each month. It’s a cycle that happens over and over again, until menopause at around the age of 50, when someone no longer ovulates or menstruates (gets their period).  

This is what happens.

Note to Educator: As you describe how eggs travel through the egg transport system, you can use your mouse or the platform’s laser pointer.

About every 3 to 6 weeks, a handful of eggs in each ovary begins to develop.

The egg that develops first — the one that gets biggest first — pops out of the ovary and finger-like structures called fibrae sweep the egg into the fallopian tube. This is called ovulation.

Around the same time that the egg begins to develop, the ovary makes increasing amounts of the hormone estrogen and the lining of the uterus starts thickening. Eventually the lining will become 5 times thicker than it normally is, to prepare itself, in case there is a pregnancy.

If there happens to be sperm in the fallopian tube when the egg pops out of the ovary, the egg and sperm have about a day to join together. If an egg and sperm don’t meet in that time, the egg disintegrates. Usually about 12-16 days after ovulation, with no fertilized egg, the uterus sheds its thickened lining of blood and tissue — this is called menstruation, or having a period, which usually lasts about 3-7 days. Most people with a uterus have periods, and it’s an amazing biological process. Without it, not one of us would be here.

Student Inquiry: Is it super clear that ovulation and menstruation are two different processes that are related? Can anyone briefly tell me how are they similar and different?

Note to Educator: If students seem confused on the difference between ovulation and menstruation, clarify. Ovulation has to do with the movement of eggs from the ovary into the fallopian tube. Menstruation has to do with shedding of the uterine lining if there is no pregnancy — which is most of the time.

Student Inquiry: Any questions, thoughts, or comments about how the egg delivery network works?

What words should we add to the word wall?

Brain break! Invite students to stretch, breathe deeply, or whatever else you usually recommend.

Fertilization — PIV sex

Student Inquiry. We have an egg. We have sperm. Now what? How does a pregnancy happen?

To create a pregnancy, the egg and sperm cells have to unite or join together. This is called fertilization.

This first lesson is about one of the ways fertilization can happen, which is through PIV sex.

Student Inquiry: Can anyone explain the basics of penis-in-vagina sex? The name gives it all away!

Note to Educator:  By asking this question you can set the expectation that this is something they are capable of doing in a respectful way. However, if you feel that it is inviting disruptive behaviour, then don’t ask the question — simply provide the following explanation:

Slide 10: PIV Sex

During PIV sex, two people bring their bodies very close together and they guide the erect penis into the vagina. The movement of their bodies causes semen to be ejaculated from the penis into the vagina.

Using a corkscrew-like motion of their tail, ejaculated sperm swim through the vagina, through the cervix, into the uterus, and through the fallopian tubes.

If the timing is right and an egg is traveling through the fallopian tube, the sperm and egg have a chance to meet.

But it isn’t that simple. Although about 200 million sperm may be ejaculated into the vagina, only 2 million make it to the top of the vagina (most are backwashed out of the vagina), 1 million through the cervix, 10,000 to the top of the uterus, 5,000 go the wrong way, and 1,000 go into the correct fallopian tube. About 200 sperm end up reaching the egg.

That is because the egg and baby transport system is like an obstacle course — sperm are blocked, destroyed and swim the wrong way.

So both the sperm and egg transportation systems play an equally important role in getting the egg and sperm together.

Slide 11: Fertilization

Sperm have an oval-shaped helmet that releases a chemical that makes an opening in the egg’s surface. Once a single sperm enters the egg, the egg’s chemistry instantly changes, locking out any other sperm. The sperm that don’t make it in, die off.

It takes about a day for the sperm’s DNA and the egg’s DNA to combine, and when they do, they form a brand new cell.  

Slide 12: Cell division

That new cell divides in half. Then in half again. And again.

The whole time it is dividing, the ball of cells, which we call an embryo, is tumbling through the fallopian tube. About a week later, when it reaches the uterus, the embryo is about 50 to 150 cells big. When the embryo implants, or or attaches to the uterus, a person is considered to be pregnant.

Note to Educator: If students mention an ectopic pregnancy, acknowledge that they are correct. Even when an embryo attaches outside of the uterus, this is also considered a pregnancy. A pregnancy test can show a positive, even though this is not a viable  pregnancy (it can’t continue to safely develop).

Sometimes two eggs pop out of the ovary and into the fallopian tube.

Student Inquiry: Who can tell me what happens if both eggs are both fertilized?

Slide 13: Multiples

If both eggs are fertilized by sperm and they both implant in the uterus, this is one of the ways we can get twins. They are fraternal twins, not identical twins. They have different DNA, because two different eggs and two different sperm started each pregnancy. That is what is shown on the right side of this slide.

Student Inquiry: Who can look at the left side of this slide and tell me how we get identical twins?

During early cell division, after the fertilized egg divides in half, those two halves continue to divide independently. They were developed from the same egg and sperm, so they have identical DNA.

Slide 14: Gestation and birth

Inside the uterus, the embryo’s cells continue to divide, then they differentiate — they take on different roles, like brain cells, eye cells, and cells that help people digest their food. Most of the time, after about 9 months of gestation, a baby is ready to be born.

There are two ways that babies can be birthed — through the vagina, called a vaginal delivery. Or through the abdomen — called a Cesarean delivery, or C-section.

Student Inquiry: Any questions, thoughts, feedback, or comments about how PIV sex works to create a pregnancy?

Miscarriage and Abortion

Slide 15: Spontaneous and elective abortion

It is important to recognize that not all eggs successfully fertilize, even when sperm are present. And, not all fertilized eggs end up implanting in the uterus. In fact, between one-third and one-half of all embryos never fully implant.

In addition, of the embryos that do implant, many end in a spontaneous abortion, or in an elective abortion.

Another word for a spontaneous abortion is a miscarriage. A miscarriage is when a pregnany ends on its own, before the 20th week of a pregnancy, often times, before anyone even knows they are pregnant. About 10-20% of known pregnancies end in miscarriage and 8 out of 10 miscarriages happen in the first 3 months of a pregnancy. Though we don’t know all the causes of miscarries, most are caused by problems with the genetic material.

In addition, about 15% of pregnancies end in an elective abortion, or pregnancy termination.

Student Inquiry: When people want to engage in PIV sex but do not want to start a pregnancy, what are some contraceptives or methods of birth control they can use?


Slide 16: Contraception

Right! Abstinence, condoms, birth control pills, IUD, injections, diaphragm, vasectomy, tubal ligation, etc. Some of these methods that are effective in preventing pregnancy don’t do a great job in preventing the transmission of a sexually transmitted infections - which is why many people also use barrier methods like condoms as well.

Note to Educator: Remind the students if you have already had this unit or when you will be having this lesson. 

That wraps up our lesson how our bodies work to create a pregnancy through PIV sex.

Final Thinking, Reflection, and Assessment (5 min)

I’d love to hear your thoughts about today’s lesson.

Note to Educator: Students can work in small groups/table-groups, to answer these questions. You can walk around the room to assess students' understanding, listen for respectful dialogue, and coach when needed. Or, if you prefer, students can share with the whole class, and you can assess understanding that way. Either way, read each question and give students 2 minutes to discuss before reading the next question.

Slide 17: Reflection

Student Inquiry:

  • When we talk about PIV sex to reproduce, who is typically included in this means of reproduction and who is left out?
  • When people are left out of the explanation of human reproduction, what messages does this convey?

Today, I did not gender any body parts or systems in the explanation of human reproduction. I didn’t make any assumptions about the sexual orientation or the gender of the people starting the pregnancy, nor did I define their relationship in any way. And, I didn’t define any particular family structure.

Student Inquiry:

  • Do you feel that using this language makes the lesson inclusive of everyone or did it make you feel that this lesson was not applicable to you, or do you have an altogether different reaction?
  • Do you think it’s important to include all individuals and family structures in the explanation of human reproduction? Why or why not?

Time Check!

Note to Educator: Depending on how much time is remaining, you can watch a video with students to introduce them to the concepts in Lesson 2 (15 minutes), or you can assign as homework (1 minute).

Intro to Lesson 2: Assign video as homework (1 min)

For homework, I am going to have you watch a short video. It introduces you to the concepts in our next lesson, when we’ll talk about all the ways to help with fertilization and all the people who can provide baby-making ingredients. Supplying reproductive material does not make someone a parent, though it can! We will discuss this in the next lesson.

Note to Educator: Choose whichever video you feel is most appropriate for your students and give them the link. Then at the start of next class, spend a few minutes to have students reflect on the video they watched.

Slide 18

  • For a basic level of understanding for students who would enjoy the silliness of this video. Students can be on the lookout for antiquated language (e.g. artificial insemination), Pregnancy and Reproduction Explained (3 minutes)

Slide 19

  • For a more proficient level of understanding, this video is a more serious and detailed explanation. Students can be on the lookout for unnecessarily gendered language (e.g. women who can’t get pregnant, woman’s ovaries)

British Fertility Society: Fertility Technologies Shaping Modern Families (7 minutes)

Intro to Lesson 2: Watch/reflect on video in class(15 min)

Note to Educator: If you did not have to do any climate setting activities, you likely have an additional 10 minutes in the period. You can use that time to watch a video that introduces the students to the concepts in Lesson 2. Choose whichever video you feel is most appropriate for your students. Then spend a few minutes and have students reflect on the video they watched.

Slide 18

  • For a basic level of understanding for students who would enjoy the silliness of this video. Students can be on the lookout for antiquated language (e.g. artificial insemination), Pregnancy and Reproduction Explained (3 minutes)

Slide 19

  • For a more proficient level of understanding, this video is a more serious and detailed explanation. Students can be on the lookout for unnecessarily gendered language (e.g. women who can’t get pregnant, woman’s ovaries)
  • British Fertility Society: Fertility Technologies Shaping Modern Families (7 minutes)

Student Inquiry: What did you think of the video? Tell me what you liked about it and what you saw as problematic. What concepts are you curious about?

Note to Educator: Have scribe write these words on the Word Wall. If not already added, students might bring up:

  • Donors: provide baby-making ingredients to someone else
  • Surrogates: Give birth to a baby for someone else

Tomorrow we will talk about all these other means of reproduction. We’ll talk about insemination and IVF. Part of that conversation will also include egg, sperm, and embryo donors, genetic surrogates, and gestational carriers. These are all people who provide baby-making ingredients. Supplying reproductive material does not make someone a parent, though it can! We will discuss this in the next lesson.

Wrap-Up (2 minutes)

Word Wall

Any other words to add to the word wall for today?

Note to Educator: Read all the words on the word wall out loud. Ask students to define any remaining words. Use this activity to assess if students understood the vocabulary and concepts from today’s lesson.

Parking Lot

Who would like to research some of the unanswered questions on our Parking Lot? You can bring your findings to our next class.

Question Box

I would like for everyone to submit questions to our anonymous question box. Grab a small piece of paper from your table. Anyone with remaining questions can

write them down, but even if you don’t have a question, I want you to draw a picture, or tell me how class was for you. That way, students that have questions will not be the only ones writing. Please put your question box paper in the question box on your way out.

Note to Educator: Many students feel self-conscious if they are the only ones submitting to the question box. It is best to have a stack of the same size/color pieces of paper at tables to be used for the question box. As an alternative, you can use an electronic platform like Padlet/Pear Deck/Menti to build an anonymous way for students to ask questions or make comments. 

Trusted Adult

You can reach out to me anytime, about today’s lesson or anything else on your mind. You can also go to a trusted adult in your life.

After the Lesson

Educator Prep for Next Lesson

Make corrections and add notes to this lesson to help you the next time you teach it!

Review Lesson 2 and gather materials, including watching the videos and reading RTF Educator Guide to Celebrity Research, if you haven't done so already.

Research answers to questions on the Parking Lot that have not been assigned to students.

Review anonymous questions that students submitted. Prepare responses for questions you’ll answer during the next class and provide resources for questions that students can answer on their own time (questions that don’t warrant class time).

Absent students can watch the videos listed in the supplemental materials and attend office hours for further questions.

Remind all students of office hours or how to get additional help with material.

Ongoing Quality Improvement

If you have comments for the authors, feedback and suggestions that would help improve these lessons in the future, please let us know! Here is a link to a Google Form.

Supplemental Resources and References

Links for Supplemental Materials

School Health Lessons (Reproduction)

Roads To Family has adapted three lessons about human reproduction, written by Advocates for Youth, 3Rs curriculum. Though these are written for younger grades, the hands-on activities can serve as supplemental materials for our lessons, even at the high school level. These lessons can be found on the Oregon Open Learning Hub,

  • RTF Modification Grade 5, Lesson 2: Puberty and Reproduction (pdf and ppt)
  • RTF Modification Grade 5, Supplement: So THAT’S How Babies are Made (pdf only)
  • RTF Modification Grade 7, Lesson 3: Reproduction Basics (pdf and original ppt)

In addition, Roads to Family has written a guide, so that educators know how to use our lessons within the scope & sequence of the 3R’s lessons. This guide also suggests other 3R lessons where more inclusive language about reproduction and family formation can be introduced. These guide can be found in the Oregon Open Learning Hub,

  • RTF Guide to Incorporating Family Concepts into 3Rs Lessons

Sexual Health Lessons (all other topics)

Free, open-sourced lessons on a variety of sexual health topics:

  • My Future My Choice, English (6th grade)

Group Agreements

Oregon Department of Education

The sexuality education resources page includes sex education laws, standards and links to a lot of other helpful educator information and resources, including a K-12 Teacher’s Guide.

Student Materials

Reproductive Health

The following organizations offer student resources on a variety of sexual health topics:, www.,,,,,,

Students that missed today’s lesson can watch this video,

British Fertility Society, Fertility Technologies Shaping Modern Families,

and choose one of the following (or watch both):, Pregnancy and Reproduction Explained,

Amaze.Org, How do LGBTQ couples become parents

Other Materials

Lesson References

References for the Lesson

UpToDate was used for the majority of the technical medical information in these lessons:

Barbieri, R. (2021). Intracytoplasmic sperm injection. In K. Eckler (Ed.), UpToDate. Retrieved August 29, 2021

Biro, F., & Yee-Ming, C. (2020). Normal Puberty. In A.G. Hoppin (Ed.), UpToDate. Retrieved August 29, 2021

Ginsburg, E. (2021). Procedure for intrauterine insemination (IUI) using processed sperm. In K. Eckler (Ed.), UpToDate. Retrieved August 29, 2021

Ginsburg, E., & Srouji, S. (2020). Donor Insemination. In K. Eckler (Ed.), UpToDate. Retrieved August 29, 2021

Matsumoto, A. & Anawalt, B. (2020). Male reproductive physiology. In K. Martin (Ed.), UpToDate. Retrieved August 29, 2021

Paulson, R. (2020). In Vitro Fertilization. In K. Eckler (Ed.), UpToDate. Retrieved August 29, 2001

Prager, S., Micks, E, & Dalton, V. (2021). Pregnancy loss (miscarriage): Terminology, risk factors, and etiology. In K. Eckler (Ed.), UpToDate. Retrieved August 29, 2021

Schattman, G, & K. Xu. (2021). Preimplantation genetic testing. In V. Barss (Ed.), UpToDate. Retrieved August 29, 2021

Welt, C. (2021). Physiology of the normal menstrual cycle. In K. Martin(Ed.), UpToDate. Retrieved August 29, 2021

As well as information from:

The American Society for Reproductive Medicine (ASRM), Reproductive Facts:

British Fertility Society (BFS),

Victorian Assisted Reproductive Treatment Authority (VARTA), Australia