Testicular morphology in the 47XXY fetus at 16 weeks gestation

The testis from two 47XXY fetuses (20 weeks) revealed histologic features not dissimilar from that observed in a normal 46XY fetus of similar gestational age. These findings support the observation that the loss of germ cells in patients with Klinefelter's syndrome is an event which begins in infancy and not in utero and progresses through early childhood and the prepubertal period. At puberty germinal aplasia may be complete with clinical evidence of testicular atrophy.