The behaviors that a culture expects of each sex is beyond the control of the individual. Everyone is born into a culture, and based on one's birth-assigned gender, certain behavioral norms are taught, encouraged, and even enforced, for example, through stigmatization when those norms are violated.
Those gender-based behaviors are to a large degree arbitrary in any given population. The standards of behavior, dress, etc. themselves are not the problem, it's the differentiation of behaviors between the two genders that is the source of GD in cross gendered individuals.
Males and females will always seek ways to physically differentiate themselves from the opposite sex beyond the natural differences in body shape and size. Preserving these appearance differences seems to be necessary for the procreation of the species. Those of us who don't conform to these norms are viewed as anomalies -- freaks of nature, if you will -- and not valued in the grand scheme of life.
Gender diversity has been with us since ancient times. Periods of acceptance and intolerance of gender variation have come in and out of fashion, as well. I think we can all be thankful that we are riding a wave of increased tolerance as the need for strict differentiation of the genders is no longer seen as crucial to the functioning of society.
Clara