Reproduction in men with Klinefelter syndrome: the past, the present, and the future.

Klinefelter syndrome (KS) is the most common chromosomal aberration in men. There are approximately 250,000 men with KS in the United States, and the prevalence of KS in male reproductive practices is 3 to 4%; however, most men are never diagnosed. KS has an effect on normal development, growth, social interactions, bone structure, and sexual and reproductive function, thus a multidisciplinary approach to men with KS is important in providing state of the art care to children and men with KS. Over the last 10 years, with advancements in artificial reproductive techniques and the successful delivery of healthy children from men with KS, the involvement of reproductive endocrinologists and urologists in the care of patients with KS is becoming commonplace. The new areas of intense research investigate optimal methods of hormonal manipulations, preservation of fertility in adolescents, and development of universal early screening programs for KS. This review provides the latest update in our understanding of the pathophysiology, natural history, and evolving paradigms of therapy in adolescents and men with KS.