Dean 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…
sexual dimorphism
There's quite a bustle among my colleagues about the deficiencies of recent studies about whether X female thingie evolved as a strategy to prevent rape. My favorite such study is one that seems to think that the only critical thing that happens when women ovulate is that they might get raped. The (probably bullshit) increase in strength, for example, one study showed couldn't be part, say of making sex more fun, could it?
Mike the Mad Biologist as always makes a cogent analysis of the general limits on that study while Greg Laden critiques speculation about tears being used to limpify…