converge. Today, the majority of American children grow up in homes where their parents share breadwinning, housework, and child care. Some couples even decide to reverse traditional gender roles, with the woman becoming the primary breadwinner or the man becoming a stay-at-home dad. For most of Western history, they didn't, because marriage was a private contract between two families. The parents' agreement to the match, not the approval of church or state, was what confirmed its validity. For 16 centuries, Christianity also defined the validity of a marriage on the basis of a couple's wishes. If two people claimed they had exchanged marital vows -- even out alone by the haystack -- the Catholic Church accepted that they were validly married. In 1215, the church decreed that a "licit" marriage must take place in church. But people who married illictly had the same rights and obligations as a couple married in church: their children were legitimate; the wife had the same inheritance rights; the couple was subject to the same prohibitions against divorce. Not until the 16th century did European states begin to require that marriages be performed under legal auspices. In part, this was an attempt to prevent unions between young adults whose parents opposed their match. The American colonies officially required marriages to be registered, but until the mid-19th century, state supreme courts routinely ruled that public cohabitation was sufficient evidence of a valid marriage. By the later part of that century, however, the United States began to