[JumpCrisscross]

> one hypothesized that it may be grouped with, fetal deformities, such as spina bifida, which are increasing not because they are advantageous, but because adverse selection pressures are diminished

Nobody seems to have studied the effects of a persistent median artery on dexterity (important amidst increasing literacy and now phone/computer use) or forearm circumference (looks hot).

[s1artibartfast]

Dexterity would be an interesting one. Whatever it is (direct or associated) must be a strong force to triple the prevalence in 150 years or so. Thats like 15% growth each 20-year generation, which would be a huge difference in reproductive success. I think this puts a pretty strong indicator that it's not a genome shift but something else