Boy or girl?
Is the skull theory accurate for predicting gender?
Myth
Not reliably. The skull theory guesses the sex from the shape of the baby’s skull on a 12-week scan, and we found no peer-reviewed study that confirms it works.
The idea is that a squarer, heavier skull points to a boy, and a rounder one to a girl. Early scans are also taken from different angles, and the baby’s position changes how the skull looks.
A better-studied option at this stage is the angle of the genital “nub”. See how accurate nub theory is. NIPT and the anatomy scan are more reliable still.
References
We found no study that tests this directly, so this answer rests on general biology and the lack of evidence for the claim.
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