Males of many species must allocate limited energy budgets between mating and parenting
effort. The Challenge Hypothesis provides a framework for understanding these life-history …

Rapid testosterone fluctuations in response to social stimuli are observed across a wide
range of species, and the highly conserved nature of these fluctuations suggests an …

Owing to humans' unique life history pattern, particularly comparatively short interbirth
intervals, early weaning, and prolonged support of multiple dependents, human females …

Scholars have long argued that the developmental state of the human infant at birth is
unique. This volume expands that argument, pointing out that many distinctively human …

Little is known about human fathers' physiology near infants' births. This may represent a
period during which paternal psychobiological axes are sensitive to fathers' new …

Partnered fathers often have lower testosterone than single non-parents, which is theorized
to relate to elevated testosterone (T) facilitating competitive behaviors and lower T …

In fathers testosterone levels are suggested to decrease in the context of caregiving, but
results seem inconsistent. In a meta-analysis including 50 study outcomes with N= 7,080 …

Humans are rare among mammals in exhibiting paternal care and the capacity for broad
hyper-cooperation, which were likely critical to the evolutionary emergence of human life …

Nurturing behavior may be critically influenced by the interplay of different hormones. The
neuropeptide oxytocin is known to promote maternal behavior and its reduction has been …

Lower testosterone levels in men are observationally associated with worse health, but it is
unclear whether they contribute to well-established social gradients in health. Mendelian …