The Economist published an article (dated April 21st, 2012) citing a study (previously published in Scientific Reports) by Oxford University evolutionary psychologist Robin Dunbar who was "interested in how investment in close relationships differs between the sexes." One conclusion of which was: ...while another was: ...in other words: "Grandma encouraged you to 'get some' mom?" ...in even other words: "Grandma's a pimp!" http://www.economist.com/node/21553003 On a side note, the method she used to gather data is interesting: Enjoy your phone call everyone!