Earlier quoted context omitted.
Actually there is a very good biological explanation for why this is the case: men are more varied than women. Because until the modern era men were expendable and the victors impregnated the women for the next generation. http://www.denisdutton.com/baumeister.htm
I don't understand how that theory would make women less varied. Successfully carrying, birthing, and raising the next generation depends almost entirely on the mother.
Look up sexual selection and dimorphism lectures from a respectable university. There's a huge body of evidence about the variation between sexes and a lot of it is beyond me since I'm not a biologist.
It explains rather well how the male population distributions get "cut off" as a result of sexual selection with constraint to resources.