Girlology: A Girl's Guide to Stuff that Matters

Sperm—the little things that a male makes that fertilize a female’s egg. Sperm are so tiny that millions of them would fit into a teaspoon. You can’t see a sperm unless you look under a microscope. If you do that, they actually look like tiny tadpoles, and they swim! It takes about 90 days for a sperm to grow and mature in the male. When they come out of the penis, it is called ejaculation. For girls, only one egg is released each cycle, but for a guy, each time he ejaculates, he lets go of many millions of sperm. Some sperm will make girl babies, and some will make boy babies, so it’s up to the man’s sperm, not the woman’s egg, to determine whether a baby boy or baby girl will be made. (By the way, the plural form of sperm is sperm. So it’s one sperm, two sperm, five million sperm.)Epididymus—a very long, coiled-up tube on the outside surface of each testicle. It’s where the baby sperm spend a few weeks while they are growing into mature sperm . . . kind of like the incubator. When a male ejaculates, the sperm come from the epididymus, travel through some tubes and go out the opening at the end of the penis.Prostate and seminal vesicles—two glands that are inside a male that add fluid to the sperm so they have something to swim in and nutrition for the trip (have snacks, will travel!). Once the fluid is added to the sperm, the mixture is called semen.Semen—we just told you what this is, but we want to make sure you realize that semen is what comes out of the penis during sex or sexual excitement (the act is called ejaculation or “coming,” and the fluid itself is called semen, ejaculate or cum). When it comes out, it amounts to less than a tablespoon of liquid, but guess how many sperm are in it? MILLIONS!!! And it only takes ONE to fertilize an egg! When ejaculation happens, all those little sperm race to see which one can get to the egg first and make a baby. Talk about competitive!

Erection Section

If you are like most girls, erections seem like a really unusual phenomenon to you. For a girl, the closest thing that happens like that and can be noticeable to others is when you are wearing a thin shirt and your nipples get hard and poke out like headlights coming on! Sometimes embarrassing, sometimes not even noticeable. For guys, erections can be even worse.

Can you imagine something between your legs suddenly becoming hard, about twice its usual size and sticking up? That’s the embarrassing thing that happens to boys when they are in puberty and beyond. Boys can get erections even as babies. It happens sometimes if they have to pee or if they rub or play with their penises. In puberty, boys get “boners” a lot more frequently because of their hormones. Erections can be unpredictable and can happen at the worst times . . . like when a guy is asked to get up in front of the class to read a report. Yikes.

Erections usually happen if a guy is thinking about something sexy or having a fantasy. It will also happen if he is “playing with himself ” or masturbating. The embarrassing part for guys, though, is that sometimes they have no control over a sudden erection. It’s certainly not something you want to point out to them like, “Um, excuse me, is that a banana in your pocket or are you having an erection?”

Most of the time, guys find a way to hide it. They either won’t stand up, or they might put their hands in their pockets to hold themselves down. (“Down boy, down!”) Sometimes they will think about something unexciting (like kissing their grandmothers) to make erections go away. These erections usually last only a minute or so when they happen like that.

A teen guy will almost definitely get an erection if he is dancing closely, body to body, with his “sweetie” or if his crush sits on his lap. If you are the subject of one of these erections, don’t worry, it’s not your responsibility to help him make it go away. Some guys might expect you to “do something” sexual to help them “finish” their sexual excitement with an orgasm (read more about that in the next section). The great news here is that ALL guys know how to take care of that all by themselves. You should feel NO obligation, and don’t let any guy tell you differently!

The other thing you might hear about is a nocturnal emission— fondly known as a wet dream. A wet dream is when a guy ejaculates in his sleep. It might happen because of a sexy dream, or it might just happen for no reason. No need to ask your guy friends about it. They won’t want to talk about it, and some guys never have one.

The Journey of a Sperm