> Until you have a controlled study on pregnant women

I wouldn’t look for a prospective randomized controlled trial of this anytime soon. Hard to imagine an IRB approving such a study.

Observational studies do suggest a small but statistically significant association between acetaminophen use in pregnancy and ASD, but the relative risk increase is small, because both the effect size and baseline risk are small.

Isn't the baseline risk for autism 1 in 30 presently?