There is one field where being wrong is free, and it is the field of telling women what to do with their own bodies. Nobody has ever lost a licence over it. Nobody has ever paid anything back. Here is a century of settled science, and what it cost the women who followed it. 1914: twilight sleep. Morphine and scopolamine, campaigned for by women's magazines as the modern humane birth. It does not remove the pain, it removes the memory of it. You are blindfolded, restrained, and put in a padded cot so you cannot injure yourself while you scream. The baby arrives too sedated to breathe on its own and has to be revived. A woman who said afterwards that something terrible had happened to her could not describe it, because that was the product. 1928: John Watson, the most cited psychologist in America, tells you never to hug or kiss your child, never to let him sit on your lap, and to shake his hand in the morning. It is a bestseller and it is government-endorsed. His own son later described the household it produced. The mothers who could not do it were called sentimental. 1930s: Truby King has you feeding by the clock. Four hours exactly, no night feed, no picking the baby up in between. A hungry infant at two hours is a discipline problem. A generation of women stood on the wrong side of a door listening to it cry, and the ones who went in were called weak. 1945: you are X-rayed to measure the pelvis, routinely, because that is the settled science. Alice Stewart proves in 1956 that it doubles the childhood cancer rate. Her funding is cut, her findings are dismissed, and the practice runs another twenty years while she is proved right slowly enough that nobody has to apologise. 1953: the trial shows DES does not prevent miscarriage. It is sold for another eighteen years by more than forty companies, to several million pregnancies. The daughters get a vaginal cancer so rare that a registry had to be built to track it. 1956: Dr Spock tells you to put the baby face down. Best-selling book of the century, most trusted man in the field. The advice runs thirty years. When it is reversed, cot death halves in every country that reverses it, and the best estimate of avoidable infant deaths across the West is around fifty thousand. Fifty thousand babies, out of one paragraph, written by a man who was certain. The mothers whose instinct said otherwise were called anxious. 1960s: shaved, given an enema, cut as a matter of routine, husband kept in the corridor. The episiotomy is justified on the grounds that a clean incision heals better than a tear. It heals worse. It tears further. Two generations of women were cut before anybody checked, and the ones who asked not to be were called difficult. 2002: HRT is stopped overnight on one badly reported trial. Twenty years of women go through menopause without it, and the correction is still crawling through the system. Not one of those was quackery. Every one had a royal college behind it, a literature behind it, and a confident man delivering it to a woman who had never wanted anything more in her life than to get this right. She was not gullible. She was obedient, on the one subject where a woman is told most firmly that what she feels does not count as evidence. And look at what every single one of them asked of her. Do not hold him. Do not feed him yet. Do not remember your own labour. Do not trust the thing your body is telling you, because a man has published on it. Sentimental. Weak. Anxious. Difficult. Every woman who got it right was given a word for it first. Her instinct was the control group nobody ran. So work out which of today's settled science your granddaughter reads back to you in disbelief. The plant-based pregnancy. The weaning pouch that is fruit purée and rapeseed oil. The exhausted woman sent to the spinach for her iron. The appetite injection handed to a woman of childbearing age, where a third of what she loses is muscle. All settled. All delivered with a leaflet and a professional smile. And not one of them funded to find out otherwise.