Defective virilisation of the male embryo (male pseudohermaphroditism) can result from defects in androgen synthesis, in androgen action, and in Mullerian duct regression, and from uncertain causes. Rarely, the defect in androgen synthesis is postulated to be either Leydig cell hypoplasia or unresponsiveness to hCG/LH, but most defects in androgen biosynthesis are due to developmental defects of the testis or to single-gene defects that impair androgen synthesis.
