Short takes

Pregnancy is full of paradoxes. As Jena Pincott points out in this entertaining look at some of the big questions about babies and birth, our stomachs are weakest when we need to nurture new life; our brains become foggy and unreliable even as we prepare for our most challenging new job. And why does a pregnant woman’s husband, whose personal odor was likely one of the reasons she was first attracted to him, now smell so awful? Pincott, a science producer whose own pregnancy features prominently in her book, digs through recent research to illuminate these and other gestational dilemmas. One of the most interesting concerns smell: When seeking a mate, we tend to go for people whose major histocompatibility complex genes (MHC, to scientists) are different from our own, because this is beneficial for our offspring. But once pregnant, many women subconsciously prefer to be around those whose MHC genes match their own - in other words, their own relatives. Not shocking, Pincott points out, since kin “may have been more helpful than mates when it came to supporting a woman during pregnancy, giving birth, and raising a baby.’’ A very interesting theory, and one that holds true in mice, but it’s still speculation as far as human beings go.