Fetal uterine position affects copulation and scent marking by adult male gerbils.

Those male Mongolian gerbils (Meriones unguiculatus) that as fetuses resided in uterine locations adjacent to no females, when adult, scent marked more frequently, mounted estrous females with shorter latencies, and ejaculated after fewer intromissions than did those male gerbils that as fetuses resided in uterine locations adjacent to two females. Both the scent-marking frequencies and copulatory patterns of adult males were positively correlated with three indices of their circulating levels of testosterone: ventral gland size, anogenital distance, and relative testes weights. Also, those males that scent marked relatively frequently copulated more reliably than did those males that scent marked relatively infrequently.