08/22/2026
So science can’t give us a perfect sibling age gap. But if we’re balancing pregnancy recovery + child development + practical parenting demands, roughly 2.5–4 years between births is a pretty reasonable “sweet spot.”
And, of course, the best spacing for an individual family may look completely different.
Studies:
Zhu BP, Rolfs RT, Nangle BE, Horan JM. Effect of the Interval Between Pregnancies on Perinatal Outcomes. N Engl J Med. 1999;340:589–594. doi:10.1056/NEJM199902253400801. (New England Journal of Medicine)
Dhamrait G, O’Donnell M, Christian H, Pereira G. Is early childhood development impeded by the birth timing of the younger sibling? PLOS ONE. 2022;17:e0268325. doi:10.1371/journal.pone.0268325. (PLOS)
Sun X, et al. Patterns and correlates of changes in sibling intimacy and conflict from middle childhood through young adulthood. Developmental Psychology. doi:10.1037/dev0001750. (pmc.ncbi.nlm.nih.gov)