“I have a couple of problems with that attitude,” says Oster. “One, I think it’s not respectful. I mean, my general sense is that… women are adults, pregnant women are also adults, and we should tell people actual evidence so they can make choices for themselves. That’s a core belief. But I also think even from an efficacy standpoint, I am not sure that this approach is actually delivering the thing you want. In part because if you tell people a thousand rules and you express them as if all of them are equally important, and people are just like: ‘Well, I can’t do all of them. Like, I can’t do all of those things,’ or like, ‘Well, I guess probably doing half of them is fine. I’ll just sort of pick whatever half I think I would like,’ then you’re actually not in a good position. Because you haven’t helped people prioritize.” A person who gets told a fully abstinent approach to cigarettes and alcohol is equally important might reason they can only achieve one, so they’ll smoke lightly throughout their pregnancy, for example. And we know that the babies of people who smoked in pregnancy have much worse outcomes than the babies of mothers who had a glass of wine a week.