I agree with all the reasons already given and think that it's a complex issue. I think the predominant factor has to be child rearing.

I do think increased technology has played a part though - making lives easier in general and blurring the lines more between traditional male and female roles.
Sarah.

Based in the UK. 2-something (2b?) hair. Very porous, fine and brittle/fragile

Hair loves: Drip drying, glycerine, shea butter, oils
Hair hates: Plopping, any kind of gel, most conditioners (scalp issues).