Reply to: Maternal capacity, twinning and fertility: the last birth matters.

This document is a reply to a study on twinning in humans. The authors analyzed a large dataset of birth records from Northern and Central Europe to understand the relationship between twinning and fertility. They found a negative relationship between the probability of a mother having multiple offspring per birth and her total number of births, challenging the idea that mothers who are more fertile are more likely to have twins. The authors argue that the differences between their study and the previous study are due to the demographic transition and that both studies support the conclusion that the heterogeneity/maternal capacity hypothesis is not supported. They caution against removing specific births from the data and encourage further exploration of complex scenarios using their statistical framework. [Extracted from the article]