Anyone who has carried and birthed a baby knows that women are not the weaker sex. And yet for thousands of years this definition has been used to stop women voting, holding power, playing sport and generally participating as equal citizens. Now there is scientific proof that women are actually stronger than men. Genetically at least. Sharon Moalem is a research geneticist and author of The Better Half, on the genetic superiority of womenSharon explains why having two Xs gives women the edge over men in every stage of life..