Over their lifetimes, approximately one in every five couples in the United States seeks infertility care. Surprisingly, only half of couples who are trying to become pregnant achieve pregnancy easily and about one in ten American couples of reproductive age are involuntary infertile; male infertility accounts for half of these cases. Despite the relative importance of infertility due to the male, infertility evaluations have traditionally focused on women, because women tend to seek gynecological care and because men often are reluctant to seek advice."