Lethal intergroup conflict has been part of the human experience ever since our species emerged on the African savannah. Modern evolutionary thinking suggests that children’s development could have evolved a variety of responses to it, some of which are highlighted upon considering, from the field of behavioural ecology, life-history theory and, derived from it, Belsky, Steinberg and Draper’s ( 1991) evolutionary theory of socialization. This speculative essay examines the implications of such thinking, specifically with regard to insecure attachment, anxiety, depression, aggression, pubertal and sexual development, as well as mating and parenting. Considered, too, are issues of intergenerational transmission and variation in developmental reactivity to exposure to deadly political violence of the ethnic-cleansing variety in childhood.