Joe and Jane desperately want to have children, and although they have tried for two years, they have not been successful. Finally, they both agree to consult a specialist, and it turns out that Joe suffers from oligospermia (a low sperm count). He doesn't understand why this would interfere with his ability to have children since he remembers from biology class that "it only takes one sperm to fertilize an egg." What should the specialist tell him?

Question

What will be an ideal response?

Answer 1

Although what Joe says is technically true (it only takes one sperm to fertilize an egg), if not enough sperm are deposited, pregnancy is not probable. Of the millions of sperm that enter the female reproductive tract, most are killed or disabled before they even reach the uterus. The acid environment, temperature, and presence of immunoglobulins in the vaginal secretions are just a few of the factors responsible for the demise of so many spermatozoa. Once inside the uterus, there is still a long way to go, and many spermatozoa are not capable of making the complete trip to the egg. Once at the egg, the sperm must penetrate the layers of cells that surround it: a feat that requires the combined enzyme contribution of perhaps 100 spermatozoa or more. If the male begins this process with too few sperm, the chance that enough will reach the egg to penetrate the egg membrane is very slim.