Abstract
Previous research has found that maternal rats discriminate male from female offspring and provide more anogenital licking to males. Two experiments were performed to determine whether this discrimination is based on hormonal condition of young. Injection of 500 .mu.g of testosterone, estradiol, or dihydrotestosterone into female pups on the day of birth led to their receiving an equivalent amount of maternal anogenital licking as males and significantly more than either oil or untreated females. The different steroids had similar effects. Maternal nonanogenital licking was not affected by sex or hormonal condition of pups, but was significantly increased by injection per se. The effects of hormonal condition or neonatal injection of young on maternal behavior were apparent 1 and 9 days after injection.