Hesperian Health Guides

A Man's Reproductive System

A man’s sexual parts are easier to see than a woman’s because they are mostly outside the body. The testicles (balls) make the main hormone in a man’s body, called testosterone. When a boy goes through puberty, his body begins to make more testosterone. It causes the changes that make a boy look like a man.

Having a Baby—Will it Be a Boy or a Girl?

a man tossing a coin in the air
Boy or girl? It is up to chance — much like flipping a coin.

About half of a man’s sperm will produce a baby boy and the other half will produce a girl. Only one sperm will join with the woman’s egg. If it is a boy sperm, the baby will be a boy. If it is a girl sperm, the baby will be a girl.

Because most communities value men more than women, some families would rather have boys than girls. This is unfair because girls should be valued just as much as boys. It is also unfair because in some places a woman is blamed if she does not have any sons. But it is the man’s sperm that makes a baby either a boy or a girl!

This page was updated:17 Apr 2019