Behavioral competition between infant care and sexual behavior in male but not female common marmosets

Sexual desire and parenthood sometimes compete in a sexually dimorphic manner, but the neural mechanism for this remains to be clarified. Here we show that, in the family-living primate common marmoset, fathers temporarily reduce infant care during the postpartum mating period leading to conception, whereas mothers do not. Functional suppression of the calcitonin receptor-expressing MPOA subregion (cMPOA) scalably disrupts infant care in both sexes and abolishes sexual behavior in males. The neuronal activation pattern induced by infant care is not identical to, but overlaps with that induced by male mating in the medial preoptic area (MPOA) of the forebrain. These data suggest that the commonality of the neural mechanism required for infant care and sexual behavior in the MPOA may lead to competition between these behaviors in fathers. Further studies are needed to identify the precise neuronal mechanism regulating this phenomenon in marmosets.