Sexual behavior in female rats born in all-female litters.

Females born in all-female litters and females stemming from predominantly male litters were compared for masculine (mounting) and feminine sexual behavior (lordosis) under various dosages of estradiol followed by progesterone and under testosterone stimulation. Estradiol did not affect mounting levels in these groups. A critical dose level was established at 0.25 mg/animal of estradiol for both groups with respect to receptive behavior. Testosterone treatment reliably stimulated mounting in these females, but no differences were determined with respect to the litter composition in utero. The results are considered as a critical and negative finding with regard to the possibility that testosterone stemming from male littermates in utero affects the female's sexual development.