No abstract

The Dutch EPP rate fits perfectly within the range reported for other contemporary and historical populations in Western Europe and was highly congruent with that estimated for neighboring Flanders, despite the socio-economic and religious differences between both populations. The estimated low EPP rate challenges the "dual mating strategy hypothesis" that states that women could obtain fitness benefits by securing investment from one man while cuckolding him to obtain good genes from an affair partner.

Highlights d Combining genetic and genealogical data illuminates our ancestors' sexual behavior d Gene-genealogy mismatches imply extra-pair paternity (EPP) d Historical EPP rates were low overall (1%) but varied depending on social context d EPP rates were highest (6%) among urban families with low socioeconomic status