A very thorough example of gender from a colonial perspective. I'd also like to add the very fascinating concept of two - spirit in Native American tribes. Before being colonised different tribes had their own ideas on gender classification. Some even had so many as 5 to 7 different genders.

It is quite an interesting phenomenon from a sociological prespective that such a social construct simply vanished under colonial rule and the two way gender classification of male and female became the default when in fact it was a primarily European construct and older civilizations had very different concepts regarding gender.

From a purely economic standpoint this colonization of gender constructs itself had a very important purpose; division of labour. Dividing the people into men and women was an easy and effective way to organize production, territory and behavior. You can refer to Fredrich Engels' works to back this up but this side of the debate slides into the capitalistic perspective of Gender as well.