How Babies are Made

Babies are made when an adult man and an adult woman love each other very much and have sex. The couple will often be in bed when the man gets sexually aroused and inserts his erect penis into the woman's vagina. The man’s sexual excitement will help him reach orgasm and ejaculate semen into the woman's vagina. Millions of sperm cells are in semen, and they will scramble inside the woman's body to get her pregnant.

Adults also have sex to show love toward each other and use birth control so as not make a baby. They can use a condom, for example, which goes on the man's penis and, if it works as it should, prevents his semen from entering the woman's vagina.

There are many types of birth control, or contraception as it is also called. 50 million to 1 billion sperm come out during ejaculation. They are extremely tiny, not visible to the naked eye, and fit in one teaspoon of semen.

The testicles make millions of sperm cells every day, which is 1,500 sperm cells per second. A girl is born with one million eggs in each ovary.