Familial male pseudohermaphroditism with normal Leydig cell function at puberty.

Four male pseudohermaphrodites from two families have been described. Although reared as females, at puberty, the timing, pattern, and degree of masculinization was similar to that of a normal male. No feminization occurred. They had normal testicular testosterone synthesis as judged by plasma testosterone, LH and FSH concentrations, as well as incubations of testicular minces with labeled precursors. Studies on cultured skin fibroblasts indicated adequate peripheral 5 alpha-reductase and normal receptor affinity and capacity for dihydrotestosterone. The histology of the testis was suggestive of a primary testicular defect. A mosaic pattern was seen: some areas contained tubules with active spermiogenesis; other areas, only Sertoli cells. These male pseudohermaphrodites appear to have a defect in fetal testicular maturation in which inadequate fetal testosterone synthesis and defective differentiation of germinal elements occurred.