The injection of 30 Mg testosterone propionate to the 5-day-old female induces a high incidence of sterility (IS) which is evident at puberty. Simultaneous injection of 10 μg reserpine, 500 μg chlorpromazine, 2500 μg progesterone, 1000 μg desoxycorticosterone acetate, or 1500 μg pregnanedione markedly reduces the IS during the immediate postpubertal period. This protection is not complete, however, as the IS approaches control levels by 90 days of age. In contrast, pentobarbital or phenobarbital affords the 5-day-old female marked protection against the effect of androgen and only ¼ of the androgenbarbiturate injected females are anovulatory at 90 days of age. The protective effect of pentobarbital is eliminated by simultaneous injection of Metrazol. Depression of neural activity is a common feature following injection of these effective agents, and it may be that this capacity underlies their protective action. (Endocrinology82: 1005, 1968)