The Little Black Book For Guys: Guys Talk About Sex

How She's Built: The Basics of a Woman's Body

In Chapter 1, you got real familiar with your own dangly parts. Well, those parts are only half the equation when it comes to making babies. And if you want to know all about NOT making babies, you’d better know about her parts, too. So here we go.

As you know, the big differences between guys’ and girls’ bodies become very noticeable during puberty. During puberty in guys, testosterone is the main hormone. In girls, estrogen and progesterone are the main hormones. This stuff tells the cells in a girl’s body to start changing. From a science standpoint, her body is setting up shop to start making and caring for babies. That’s why, during puberty, a girl’s breasts grow (to feed a baby), her hips get wider (to birth a baby), and her period starts (to get rid of the egg that didn’t get turned into a baby that month). The actual baby-making parts are all on the inside:

Ovaries

These suckers are the factories where estrogen and progesterone get made. They’re also the warehouses for those eggs that are needed to make a baby. These are damn impressive warehouses too—a woman has her entire lifetime supply of eggs stored in there!

Fallopian Tubes

Sounds like a subway system, and they sort of are. The fallopian tubes are like the train tunnels that the eggs travel through to get to the uterus. After spending all that time in the warehouse (ovary), every month an egg gets to ride a fallopian tube to the uterus for a night on the town with any sperm there to meet it. Sperm is supposed to wait at the station (in the uterus), but sometimes it sneaks its way into the fallopian tubes to find an egg early—horny little bastard. That’s bad news though, because if that sperm and egg hook up in the tube, that’s where a baby will start growing. But the tube just ain’t equipped to support a baby. This can be very dangerous for a woman and it’s called an ectopic pregnancy, but luckily it’s rare.

Uterus

The uterus is where the real action takes place. And by action, we mean pregnancy. The egg comes riding in from the fallopian tubes looking to get it on with some sperm. No sperm there yet? Egg doesn’t mind kicking it and settles into the uterus to await the arrival of the sperm. And why not? It’s a bad-ass crib for chilling: the walls of the uterus form a thick coating like a sweet cushion. If any sperm comes into the uterus and finds an egg, then crank up the Barry White ‘cause it’s time for a booty call. The sperm enters the egg and then the egg settles into those cushions… and stays there. A sperm and egg together in that cushiony wall of the uterus means that a girl becomes pregnant. If the sperm is a no-show, the egg won’t wait around forever. Egg gathers up all the cushions (the coating of the uterus) and leaves through the vagina. And that’s what’s happening when a girl gets her period.

Cervix

The cervix is the opening into the vagina from the uterus. Some birth control methods stop sperm from getting in by placing a barrier over the cervix during sex. It’s like closing the door so sperm can’t get in.

Vagina

The vagina is the opening that leads from the outside of the body to the cervix and on to the uterus. Vaginal sex means having sex by moving the penis in and out of the vagina. The vagina has strong muscles that tighten around a guy’s penis. 

This is what gives guys that enjoyable sensation during sex. And that enjoyable sensation can lead to ejaculation: semen goes squirting into the vagina unless it’s trapped inside a condom.

If fallopian tubes are like the subway for eggs, semen is like the bus for sperm. Millions of sperm can ride in just a teaspoon of the stuff. If sperm is released into the vagina, it will travel up to the uterus in search of an egg, like horny guys on Spring Break, heading to Florida in search of hot chicks. The only job sperm has is to seek out eggs and join with them to create a baby. Sperm is very good at its job and even sperm released outside and near the vagina can make its way into the uterus!