Really? Nothing at all to do with gender bias, societal expectations and stereotyping built up over centuries? Yes, there are some jobs that men on the whole will do better than women because of the physical strength but being a leader is not one of them.
Any way, I'm done - you just carry on...
Just repeating that men make better leaders doesn't make it true.
Some women are seen as strong, capable, able to perform under pressure some men aren't.
But you said "men make better leaders"; you now seem to be saying "men make better leaders when fighting is involved which the leader may have to be involved in," not quite the same thing..
Do you really believe that the reason that there have been so few women leaders throughout history is due to leadership ability? If that is the case, why are there so many more female leaders now than there were 50 years ago (let alone 150 years ago)? Have women somehow got better at leadership...
School uniform rules are an area which have caused a problem for a number of schools, for example many schools have had rules that say girls can wear a small pair of earstuds but boys are not allowed to wear any sort of ear jewellry. A boy at a school near me was sent home for wearing earstuds...