Two to three kids may be healthiest for longevity, study finds

A Nature Communications-backed study of about 15,000 Finnish women shows a U-shaped relationship between number of births and aging/mortality: women with two to three children age biologically slower and have lower early death risk, while those with no children or many children (around seven) age faster and face higher mortality. The researchers used epigenetic age markers and caution that the study is observational, so it cannot prove causation. Potential explanations include resource allocation over a lifetime (disposable soma theory) and benefits or health reflections of childbearing, with never having children possibly linked to poorer health. The authors advise against changing personal family plans based on these findings alone.