The Chinese traditionally make babies sleep on their backs. You should check out their historical autism rate
We were looking for natural experiments. Ideally somewhere that babies are still stomach slept. Much like Israel and peanut snacks in the study of peanut allergies, it’s hard to change a protective paradigm without a natural experiment.
https://www.sciencemag.org/news/2015/02/eating-peanuts-preve...
https://www.washingtonpost.com/archive/politics/1993/06/30/c...
The WaPo article is very illuminating re: how Chinese babies were raised. As it was published almost 30 years ago, those babies are now established Chinese adults. Makes you wonder how much they're shaped by how they were reared.