...This is the story of our times—the story of the family, once a dense cluster of many siblings and extended kin, fragmenting into ever smaller and more fragile forms. The initial result of that fragmentation, the nuclear family, didn’t seem so bad. But then, because the nuclear family is so brittle, the fragmentation continued. In many sectors of society, nuclear families fragmented into single-parent families, single-parent families into chaotic families or no families. If you want to summarize the changes in family structure over the past century, the truest thing to say is this: We’ve made life freer for individuals...