Most of the advance buzz about The Business of Being Born has centered around an image of its producer, Ricki Lake. Naked. Giving birth. In a bathtub. If you couldn’t handle the crowning scene in Knocked Up, you should probably pass on this one; not only is Lake’s real labor about a million times more explicit (she flops and writhes for a long while, then a gunk-covered infant slowly emerges from between her legs), but we see quite a few other women popping out babies as well, in every imaginable contortion. Even the director, Abby Epstein, joins the club, turning the camera on her own attempt at natural childbirth for her doc about the birthing biz. The tone of the film is polemical, occasionally strident, and some of its balder assertions need to be taken with a damn big grain of salt (one “expert” claims that mothers don’t bond with babies delivered by c-section, and that the proliferation of caesarians in the West portends the end of love). There’s also an obliviously upper-class, sanctimoniously yuppie-crunchy slant to the whole production. Still, Epstein and Lake have crafted an absorbing, thought-provoking inquiry into what modern birth has become and how to make it better.