I think we need a serious grain of salt with this study. It was a phone survey, to start with, where they called twice during the pregnancy and once six months after. As is pointed out in the article, they didn't ask how much acetaminophen was taken, nor did they ask why.

Given that there's nothing else the doctors will let you take, it's not surprising that 56% of the women took acetaminophen.

They've come up with what may be a correlation, but it's certainly not any proof of a causation.