Читать книгу Sex For Dummies - Pierre Lehu A., Dr. Ruth K. Westheimer - Страница 43

Despite the fact that a variety of contraceptive methods have allowed people to disconnect sexual intercourse from reproduction, the main purpose of having sex, from an evolutionary point of view, is still to make babies. But, although the penis is required to penetrate the woman’s vagina for the best chance at success, the man needs seeds to place within her to accomplish this important task. These seeds, called spermatozoa (or more often by their nickname, sperm), are manufactured in the testicles.

Sperm are rather amazing little creatures. They are the only parts of the body that do their work outside of it. You see, sperm don’t survive well at high temperatures, particularly the temperature inside our bodies. This is why the testicles lie outside the body where they can be cooled by the soft summer breezes (at least for those of you who favor kilts or loincloths).

For the sperm to be successful at their task of making babies, they have to overcome many obstacles after making a long journey. You may well recognize their final shape — an oval head with a long tail that helps to propel them along — but sperm don’t start out that way (see Figure 2-4).

Illustration by Kathryn Born

FIGURE 2-4: The sperm: independent, a good swimmer, and a heckuva guy.