The most heavily anticipated economics book of the year makes a radical argument: Having married parents is good for kids.I know, I know. It seems like a joke, right? Of course having two involved parents living in a stable home together is good for kids. Anyone who has considered having children with a partner or was ever a child themselves must know that. But for years, academics studying poverty, mobility, and family structures have avoided that self-evident truth, the economist Melissa Kearney writes in The Two-Parent Privilege, released this week. And while the wonks avoided the topic, the rise of single-parent households in America exacerbated inequality and contributed to astonishingly high rates of child poverty.