Conception is possible only during a few days in the middle of a woman's menstrual cycle, when she releases her egg. The release of the egg is called ovulation. In an infertile couple, either the man or the woman may contribute to the problem.
Male infertility is the inability to initiate a pregnancy due to a problem with the male partner.
Frequently, the infertility results from an insufficient quality or quantity of sperm. Male infertility is not the same as impotence, which is the inability to have an erection. About one in ten American couples of reproductive age are involuntarily infertile, half because of male infertility. In another four in ten, infertility results from voluntary surgical sterilization or from diseases of medical or surgical origin. Despite the relative importance of infertility due to the male, infertility evaluations have traditionally focused on women, because while women tend to seek gynecological care, men often are reluctant to seek advice.