[Feminization: a paradoxical effect of stimulation with hCG/hMG in the infertile male]

Male feminization is an uncommon and complex phenomenon which occurs as a consequence of an imbalance in the effective oestrogen/androgen relationship. One of the many approaches used in the treatment of idiopathic male infertility is hCG/hMG stimulation. This paper reports one case of an infertile male treated with hCG/hMG after surgical correction of a varicocele, which resulted in a feminization effect evidenced by gynaecomastia and severe spermatogenesis blockade. When therapy was discontinued the feminization disappeared, a rebound phenomenon with normalization of most of the seminal parameters being seen. No other fully documented cases were found in the literature. Finally, the pathoetiological mechanisms involved in the feminization are analyzed and a revision is made of the causes that may cause it.