The present and future state of hormonal treatment for male infertility.

Although male factors contribute to over half of all cases of infertility, most infertile men are described as 'idiopathic oligo/asthenozoospermic' rather than diagnosed precisely; hence, specific medical treatment is not possible. One uncommon but treatable cause of male infertility is gonadotrophin deficiency in which gonadotrophin replacement therapy is highly effective at inducing spermatogenesis and fertility. Hormonal therapy is a logical approach for empirical drug therapy given the fundamental role of hormonal regulation in spermatogenesis. However, treatment with GnRH analogues, gonadotrophins, androgens, anti-estrogens, aromatase inhibitors, growth hormone- and prolactin-suppressing drugs is ineffective in unselected infertile men. Prolonged high-dose glucocorticoid therapy for sperm autoimmunity may improve pregnancy rates modestly, but the risks are generally unacceptable compared with IVF or ICSI. For these reasons, modern reproductive technologies, notably ICSI/IVF, have become the de-facto standard empirical treatment of male infertility, despite involving significant though infrequent risks to the fetus and mother. There remains a potential for hormonal methods to improve sperm quality or ultrastructure in subgroups of infertile men more responsive to hormonal manipulation or using novel protein or gene-targeted therapies or biochemical approaches based on post-hormonal receptor mechanisms that stimulate spermatogenesis. How such novel hormonal methods will develop in conjunction with improved ICSI/IVF or cloning technologies, and the potential role of adjunctive hormonal therapy remains to be clarified.