Genetic causes of male infertility: current concepts.

Infertile men with severe spermatogenic defects and low or no sperm counts have a significantly higher rate of genetic abnormalities than fertile men. The fact that intracytoplasmic sperm injection can potentially bypass natural selection barriers to genetic disease transmission has brought a sobering but important impetus to recent research in the area of genetic infertility. Recent studies have focused on examining the prevalence of certain genetic defects in infertile men, analyzing the molecular basis of infertility in genetic disorders, and detecting new causes of genetic infertility. Several novel research findings deserve mention for their potential impact on genetic infertility. It has been demonstrated that elongated and round spermatids can be successfully injected into human oocytes and viable births obtained. Likewise, significant advances have been made in the arena of interspecies germ cell transplantation. Of some concern is the finding of a relationship between faulty DNA repair and infertility in men with severe testis failure. This review summarizes the recent genetic advances in these areas of male genetic infertility.