The Reproductive Tract

Neonatal thymectomy of mice, when no ectopic thymus existed, constantly resulted in developmental arrest of the ovary but not of the testis; it also caused sterility in the female. The ovaries of thymectomized mice were extremely small and were characterized by absence of follicles and corpora lutea. Such an ovarian dysgenesia was observed when the mice were thymectomized at 3 days of age, but not at 7 days or later; it was prevented by thymus grafting.