This article looks into the social construct of how we attach meaning to colors and clothing. Gender is socially constructed that associates certain traits or behavior as feminine and masculine. Pink has been associated with girls while blue with boys, this as this article explains, this was not always the case! So our idea of gender changes over time and place.
The whole “nature vs. nurture”… While I thin it’s a lot of nurture, I can’t ignore the possibility that it might be both. For example, take the book As Nature Made Him: The boy who was raised as a girl by John Colapinto. The infant boy’s penis was cut off when he was been circumcised, so the doctors advice to turn him into a girl and never disclose this to the boy. The boy took estrogen hormones over the years and grew up as a girl, however, her attraction was for women… eventually the truth came out, as no matter how much nurture this boy was into the role of a girl, it didn’t work.
Anyway, this is an interesting article that tells you how dressing is gendered… and that in other times boys used to wear dresses.