Before you can feel confident in any kind of sexual or romantic experience, it helps to understand your own body. Learning about how human bodies work—yours and others’—isn’t weird or gross. It’s normal. It’s part of growing up, and it gives you the knowledge to make smart, respectful choices.
This chapter will introduce the basics of anatomy for both male and female bodies, talk about how bodies respond to sexual feelings, and explain some of the natural differences that exist—including intersex bodies.
People born with male bodies usually have:
Penis – The external sex organ. It becomes erect (hard) when someone is aroused (sexually excited).
Testicles (or testes) – Two small organs that produce sperm and testosterone (a hormone).
Scrotum – The skin that holds the testicles. It helps regulate temperature for sperm health.
Urethra – A tube inside the penis that carries urine and semen out of the body (not at the same time).
Female Anatomy (Typical)
People born with female bodies usually have:
Vulva – The outside parts of the female genitals, including the labia (folds of skin) and clitoris (a sensitive area that can feel good when touched).
Vagina – A muscular canal inside the body. It connects the outside of the body to the uterus.
Uterus – Where a baby can grow during pregnancy.
Ovaries – Two small organs that release eggs and produce estrogen and other hormones.
Menstruation (a period) – A monthly cycle where the uterus sheds its lining. It’s a natural part of the body’s reproductive system.
Arousal and How Bodies Respond
When people feel sexual attraction or desire, their bodies may react physically. This is called arousal.
Some examples of what might happen:
Penises can become hard (erection).
Vaginas can become wet (lubrication) to prepare for sex.
Breathing can speed up, and the heart might beat faster.
Touching certain areas, like the genitals or nipples, may feel good.
Arousal is natural. You don’t need a partner to feel it—it can happen during self-exploration, thoughts, dreams, or even for no clear reason at all. It doesn’t mean you have to do anything. It’s just your body doing what it’s designed to do.
Masturbation means touching your own body, especially your genitals, to feel good or explore what feels pleasurable. It’s a private way to learn more about yourself, and it’s completely normal. It can also help relieve stress and give you a better understanding of what you enjoy.
There’s nothing wrong with masturbation, and it doesn’t hurt your body or make you weird. Some people do it, some don’t—it’s a personal choice.
Not everyone’s body looks or functions the same way. Some people have larger or smaller genitals, some develop faster or slower during puberty, and some people don’t fit neatly into “male” or “female” categories.
Some people are intersex, meaning they’re born with physical traits that don’t fit the typical definitions of male or female. This might include differences in chromosomes, hormones, or anatomy. For example, someone might have both ovarian and testicular tissue, or their genitals might not look typical.
Being intersex is natural, and it happens in about 1 in every 1,500 births. Intersex people may identify as male, female, or nonbinary—it depends on the person. What’s most important is that everyone deserves respect, no matter what their body looks like.
Everyone’s Body is Valid
You might be curious about how your body compares to others. That’s normal. But try to remember: there is no "perfect" or "normal" body. Everyone’s different, and that’s okay. Learning about your body is the first step in understanding yourself and respecting others.
Coming up next, we’ll explore what sex actually is—emotionally, physically, and socially—and clear up some common myths and misunderstandings. But first, take a moment and show yourself what you have learned.
Thinking Questions:
1. Why is it helpful for everyone—not just girls—to learn about the menstrual cycle?
2. How does knowing correct anatomy terms help someone talk about their body more confidently?
3. What can a person do if they feel uncomfortable or embarrassed learning about reproductive anatomy?
4. Why is it important to understand that not everyone’s anatomy fits into typical male or female categories?
5. How can learning about anatomy lead to more respectful and safer relationships?