While each individual has 10 billion ancestors a thousand years ago, these are not distinct and in practice, the number of distinct ancestors is much smaller. A female (‘mitochondrial Eve’) and a male ancestor (‘Y-chromosome Adam’) of all humans certainly existed,...

This study investigates whether a female’s entry into motherhood is influenced by the kin orientation of her social network. We use data from the British Household Panel Study (BHPS) and define kin orientation as the number of relatives who a female reports within her three closest...