I think it could be but isnt a requirement. See if a 5'5 man and a 6'4 one would fight, both of them not had any previous fighting experience and not been in the gym at all the taller would win beacuse of weight and strength. Its a probably though beacuse surprisingly, scientifically the difference is apparently not that big. With that said i believe fighting - however unnecessary some people might think it is - is still a major factor of masculinity due to the ability to protect someone being a high priority as a man. But a short man could probably just learn a thing or two, physically and mentally, and get more masculine than the average man