Mothers with higher twinning propensity had lower fertility in pre-industrial Europe.

ABSTRACT: Historically, mothers producing twins gave birth, on average, more often than non-twinners. This observation has been interpreted as twinners having higher intrinsic fertility - a tendency to conceive easily irrespective of age and other factors - which has shaped both hypotheses about why twinning persists and varies across populations, and the design of medical studies on female fertility. Here we show in >20k pre-industrial European mothers that this interpretation results from an ecological fallacy: twinners had more births not due to higher intrinsic fertility, but because mothers that gave birth more accumulated more opportunities to produce twins. Controlling for variation in the exposure to the risk of twinning reveals that mothers with higher twinning propensity - a physiological

SUBMITTER: Rickard IJ 

PROVIDER: S-EPMC9130277 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature