Who and When was it decided?

I find it so intresting that in America we tend to categorize what is Fem and what is Masculine. We as humans like to define what, when and who. We like to fit people into boxes and when we cannot we tend to reject them. From before we are born the ultrasound "it's a girl/boy". Oh Pink for a girl and blue for a boy. Girls will play with dolls and wear dresses and boys will play with trucks and wear jeans.

Being blessed to live and work in other countries I saw societal norms and religious dictator of what was worn. I'm a people watcher um because I love clothing fashion and the why's behind what is chosen.

So my question is do you let society or religious beliefs dictate what you classify what is femenim and what is masculine?