When are gender roles adopted?

My guess is the moment you are born. Right from day one, you are treated as a boy or a girl. You get wrapped in a pink or blue blanket. A documentary on this showed how adults treated baby boys and girls differently. They would try babies of both sexes and have them dressed in boy clothing and girl clothing, and the adults treated those in pink more tenderly and affectionate than those dressed in blue.

However, not all aspects of gender are learned. Some are apparently instinct. They experimented with very young children who were too young to be fully indoctrinated into gender roles. They gave the toddlers special dolls that were designed to break after so much play. The boys either tried to fix it or they found it amusing. The girls either cried or tried to let the adult know about the problem.