Evolutionary psychology may be able to explain this phenomenon. Women evolved to be dependent and choosy due to their greater parental investment. This caused men to evolve to be taller and stronger in an evolutionary arms race competing for mating opportunities. In response to this, women are thought to have evolved to choose the strongest and most dominant man available to be protected from men attempting to coerce them into sex, male violence in general (bodyguard hypothesis; Wilson & Mesnick, 1997)
Okay then why don't we have people who are 12ft tall have have hyper strength.