How Sex Works

From the time we are teenagers through mid-life or longer, we are capable of sexually reproducing. Sex plays a major role in much of our culture -- we see it in our fashion, literature, music, television and movies.

From a biological standpoint, the goal of sex is to merge two sets of genetic information, one from the father and one from the mother, to make a baby that is genetically different from either parent.

Fertilization
The primary goal of sex is to merge the sperm and egg (fertilization) to make a baby. In many organisms, sex occurs outside of the body. For example, in most fish or amphibians, females lay eggs somewhere (usually on the sea/river bed), the male comes along and sprays the eggs with sperm and fertilization takes place.

In reptiles and mammals (including humans), fertilization takes place inside the body of the female (internal fertilization). This technique increases the chances of successful sexual reproduction. Because we use internal fertilization, our sexual organs are specialized for this purpose. Let's take a closer look at the sexual organs in males and females.