There is already evidence for an adaptive neural mechanism through which the perception of cuteness as a feature of the BS is most likely promoted in humans. Accordingly, cute baby faces have repeatedly yielded activations of regions of the mesolimbic reward system8,9. For example, Glocker et al.10 observed an increase of activation in the nucleus accumbens in women while evaluating pictures of babies with increasing BS (i.e., low BS < unmanipulated BS < high BS). Interestingly, the mesolimbic reward system may also be highly responsive to the influence of two hormones that have opposing roles in human nurturing behaviors. Firstly, a high oxytocin (OT) receptor density can be found in the mesolimbic reward system of social mammals11 and increased activation of the ventral tegmental area to images of crying infants after OT treatment suggested that OT influences the reward value of stimuli carrying the BS12. Further, OT administration increased the preference for pictures of young children. This preference was determined through rs53576G homozygote participants (a polymorphism in the OT receptor gene)13. Finally, OT has been consistently associated with higher maternal attachment and increased caretaking in humans14,15. The androgen testosterone (T) may also have reinforcing effects in the mesolimbic reward system16. Yet, in contrast to OT it may compromise behaviors associated with maternal care (e.g. nurturing)17. Previous studies have noted a reduced T level during early parenthood and this decline appeared to be associated with the quality of childcare18–22 (but see23).