Responsiveness to testosterone of male gerbils from known intrauterine positions.

Following either a) castration or b) both castration and implantation with capsules releasing a constant, physiological dose of testosterone, adult male Mongolian gerbils that had matured in intrauterine positions between two male fetuses still scent marked with greater frequency than did male gerbils that had matured in intrauterine positions between two female fetuses. We also found significant positive correlations between the relative frequency of scent marking exhibited by individual male gerbils when intact, after castration and after both castration and implantation with capsules releasing testosterone. Each of these findings is consistent with the view that differential exposure to testosterone, as a consequence of fetal intrauterine position, has lasting effects on the organization of scent-marking by male gerbils.