Squash preparation studies of germ cells in human fetal testes.

Testes from human fetuses 21 to 41 weeks of gestation were investigated using a modified squash technique. At all of the gestational ages examined, 90 to 95% of the germ cells were in interphase. Preleptotene germ cells, which exhibited densely staining condensed clumps of chromosomes, were found in all samples studied and constituted 3 to 9% of the germ cells observed. In appearance they resembled preleptotene figures seen in the fetal ovary. Occasionally, germ cells containing slender chromosomes with a beaded appearance, but without prominent condensation, were encountered. These cells were interpreted as preleptotene germ cells in the early stages of degeneration. Germ cells in other meiotic stages were not observed in this study.