Today in America, four out of five families fall outside the traditional notion of a mom at home and a dad at work and a bunch of kids in the yard with the picket fence. And while some certainly see this as a cause for concern, arguably a similar majority does not. Just as our idea of America — of race and citizenship and belonging — have expanded, albeit with great struggle, over the centuries to include new communities and identities, our idea of family is always expanding. Whether it’s grandparents raising their grandchildren or single mothers adopting children on their own or families like mine with two parents of the same-sex or families blended by second (or third or fourth) marriages, our ideas and even our ideals about what makes a “family” have stretched to accommodate reality. Today, a majority of Americans support same-sex marriage — just one sign of how our collective definition of family is evolving, for the better.