Fluctuations in the number of germ cells during the late foetal and early postnatal periods in boys.

Previous studies have shown marked elevations of serum concentrations of follicle stimulating hormone, luteinizing hormone, and testosterone during the first 6 months of life in boys. We have carried out a quantitative study of the changes in the total number of germ cells in 46 pairs of autopsy testes from normal boys between 28 weeks of gestation and 1000 days of postnatal life. The study demonstrated an increase in the total number of germ cells in boys up to 100 days of age (Spearman rho = 0.62, P less than 0.01), and a successive decrease in boys older than this age (Spearman rho = -0.56, P less than 0.01). Thus a peak in the total number of germ cells per boy was found somewhere between day 50 and 150 after birth, and the course of this variable was similar to that previously reported on the hormonal concentrations in serum.