Filched this from KF's RMK thread:
For better or worse, evolution has optimized women's bodies for the extreme endurance reproduction triathlon: first you spend nine months growing a little human being inside of you, then once it's the size of a cannonball you spend several agonizing hours pushing it out of you, then you spend another nine months or so feeding it from your own body. No male will ever qualify for this event, let alone be a champion at it.
(Side note: saying that the realities of mammalian reproduction have shaped the evolution of human anatomy is not the same thing as saying that women are baby-making machines. Women are more than walking incubators in the same way that men are more than walking sperm banks.)
The fact is that female reproductive abilities demand a tradeoff in terms of speed and strength. Testosterone above ~2.4 nmol/L (which is well, well below the male norm) derails the hormonal cycle that governs the growth of endrometrial lining and ovulation. (I won't go into all the effects that T levels have on athletic performance, but suffice it to say that these effects are real and huge. The low-T elite male athletes Rhys loves to yammer on about have low T because they've borked up their endocrine systems by doping.)
The uterus takes up valuable real estate in the body cavity, meaning that men have proportionally larger internal organs, including heart and lungs. Men breathe more efficiently than women: women's breathing relies more on expansion of the ribcage, while men's breathing relies more on the diaphragm, because men will never have a tiny little human inside of them pressed up against their diaphragm. Men's Q angle is biomechanically better suited for running (and maybe cycling? can any cyclists or medical folks weigh in on this?) because they don't need pelvises wide enough to accommodate an infant's head. Women have more body fat than men because it is necessary to sustain ovulation, pregnancy, and lactation; even elite female athletes who have too little body fat to menstruate will still have significantly more body fat than elite male athletes (that is, elite male athletes who are competing as males—I'm lookin' at you, R).
Bottom line: men have a huge athletic advantage over women. No amount of wishful thinking and rhetorical shell games will alter this fact. This is not to say that women's athletics don't or shouldn't matter. No human man could outwrestle a grizzly, outswim a dolphin, or outsprint a cheetah, but we still celebrate human men who excel at wrestling, swimming, and sprinting relative to other human men. There's no reason that we can't do the same for women.