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Human Birth Constraints Not Unique, Study Finds Across Primates

6/30/2026

Summary

Story summary

A Nature Ecology & Evolution study found human childbirth is constrained but not uniquely among primates.
Researchers created 3D models from pelvic and cranial scans of 130 adult females across 29 primate species.
Squirrel monkey newborn heads are almost twice the size of the maternal pelvic inlet, producing an extreme fit.
Co-authors Nicole Torres Tamayo and Lia Betti said the results correct human-centric bias and revise the obstetrical dilemma concept.

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Story summary

A Nature Ecology & Evolution study found human childbirth is constrained but not uniquely among primates.
Researchers created 3D models from pelvic and cranial scans of 130 adult females across 29 primate species.
Squirrel monkey newborn heads are almost twice the size of the maternal pelvic inlet, producing an extreme fit.
Co-authors Nicole Torres Tamayo and Lia Betti said the results correct human-centric bias and revise the obstetrical dilemma concept.