Hand stencils
gregladen | March 25, 2014Dean Snow was one of my two advisors in undergraduate school. I have fond memories of all six months of college. But that's another story. Anyway, several years ago, Dean got wind of the research showing that humans exhibit sexual dimorphism in the ratios of the middle digits of the hand. It is believed that this is accounted for by differential rates of bone growth during early development that happen to be different, on average, between males and females. There is probably not an adaptive explanation for this. Rather, at some important developmental stage there is an endocrine effect…