Around the globe, we're witnessing an explosion of new family structures. In the US, cohabitation has doubled since 1990 and 41% of births are to unmarried women. Twice as many Britons have mixed-ethnic parentage compared with a single ethnic background. And in Australia, nearly half of same-sex couples are raising two or more children. As USA Today said: "Whatever a traditional family used to be, it is no longer."
