It was often male doctors who dispensed such advice — the same cohort that was so sure of its expertise that it unwittingly infected laboring mothers with puerperal fever in maternity hospitals during the 18th and 19th centuries. Doctors blamed the epidemic on sour breastmilk, tight corsets, bad air; it took a while before they grudgingly bought into the germ theory of disease and started to wash their hands between patients and after autopsies.

Traig’s book is filled with tales of men telling women what to do, and she’s candid about how furious it makes her. She calls one eminent 19th-century doctor “A PATRONIZING CHAUVINIST” (the all caps are all hers; she later admits that her go-to disciplinary move with her own children is to yell). Old medical textbooks, from the ancient Greeks through the medieval Europeans, are filled with men’s specious assertions about feminine hygiene: “I think we can agree that anyone who feels qualified to hold forth on something he has no actual knowledge of can, rather accurately, be called a douche,” she quips.

She isn’t wrong, but the nonstop vaudeville can get wearying. Some of her punch lines are so broad that they should be accompanied by a sad trombone. She describes the Puritans arriving to America “like a wet, smallpox-infected blanket to put a damper on all the fun” (genocide, amirite?). Lewis Carroll’s creepy overture to a young girl “starts to sound an awful lot like an invitation to a pool party at Roman Polanski’s.”

Parenting is a subject that generates so much piety that you can’t fault Traig for having a sense of gallows humor, though the calibration is off. Part of this has to do with how skillful and fluid a writer she is otherwise — the facts seem to tumble forth, in a way that makes her jokes feel superfluous (when they aren’t awful) and strenuous (when they are). Much of the story she tells is pieced together from other books, including Ann Hulbert’s “Raising America” and Sarah Blaffer Hrdy’s “Mother Nature.” Still, it’s a fascinating narrative, tracing the long history of mistakes and reversals and cultural presuppositions that have structured our most intimate relationships.

Depicting herself as both extremely lazy and extremely anxious, Traig says that what she wants the most as a parent is some reassurance that she isn’t doing it wrong: “Parenting is so hard; and like our kids, we’re all looking for permission to slack off in some areas.” Sometimes, though, Traig can’t help herself, declining to step away from the kid or the joke. “Doing nothing,” she admits, “is often the hardest thing to do.”