Testosterone probably has some role in how the genders behave and how these behaviors have become codified by most societies, although as I understand it, studies trying to link testosterone levels to aggression have generally been inconclusive. It does seem to have effects on sexual aggression and general risk-taking. While it may not necessarily make men more physically violent, it might make them more assertive and more aggressive in social settings. And its effects on muscle growth may also have an effect in that regard, as a stronger person may feel more confident in acting assertive or aggressive.
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould
