Infertility is the failure of a couple to become pregnant after one year of regular, unprotected intercourse. In both men and women the fertility process is complex. Even under ideal circumstances, the probability that a woman will get pregnant during a single menstrual cycle is only about 30%. And, when conception does occur, only 50 - 60% of pregnancies advance beyond week 20. In many cases, infertility is caused by a combination of problems in both partners that conspire to prevent conception from occurring.

About 8 - 10% of couples of reproductive age experience infertility, and in around 40% of these cases male infertility is the major factor. Another 40% of infertility problems are caused by abnormalities of the woman's reproductive system, and the remaining 20% involve couples who both suffer reproductive difficulties.

Infertility affects one in 25 American men. More than 90% of male infertility cases are due to low sperm counts, poor sperm quality, or both. Whether sperm counts are declining overall in industrialized countries is a controversial issue. However, over the last few years the number of assisted reproductive procedures that target male infertility have increased, while female procedures have declined.

Sperm picture
The male reproductive system creates sperm that is manufactured in the seminiferous tubules within each testicle. The head of the sperm contains the DNA, which when combined with the egg's DNA, will create a new individual. The tip of the sperm head is the portion called the acrosome, which enables the sperm to penetrate the egg. The midpiece contains the mitochondria which supplies the energy the tail needs to move. The tail moves with whip-like movements back and forth to propel the sperm towards the egg. The sperm have to reach the uterus and the fallopian tube in order to fertilize a woman's egg.