Serum Müllerian Inhibiting Substance Assay — A New Diagnostic Test for Disorders of Gonadal Development

Half a century has passed since Alfred Jost1 postulated that male sexual differentiation is mediated by two discrete substances produced by the fetal testis and that, in their absence, sexual differentiation proceeds to the female phenotype. During embryogenesis, fetuses of both sexes develop two pairs of genital ducts associated with the mesonephros and the undifferentiated gonads. The müllerian ducts have the potential to differentiate into the fallopian tubes, uterus, and upper part of the vagina of the female reproductive tract, whereas the wolffian ducts differentiate into the vas deferens, epididymides, and seminal vesicles of the male reproductive tract. For normal . . .