Bisphenol A (BPA) is a component of some plastics and is found in food containers, plastic water bottles, dental sealants, and thermal receipt paper. In the body, BPA is a mild synthetic estrogen, one of the gigantic class of chemicals called "endocrine disruptors", even if they are 1/20,000th able to bind as well as the actual estrogen.
Environmentalists claim that despite the FDA doing an exhaustive four-year study and finding no effects, even in pregnant mice, despite feeding them 1,000 times as much BPA as a human can get, and affirming that humans process and excrete BPA far more efficiently than rodents, that a magical hormesis effect is still causing problems.
When advocate against BPA can't use toxicology, they use epidemiological suggestion, in this case that 241
expectant mothers who had even trace levels of BPA in their urine, and then trace level in the kids at ages 3-5, were more likely to result depressed boys at ages 7-9 and 10-12.
If you know anything aout statistics, you can see the flaws in the inference by the Mailman School of Public Health published in the journal Environmental Research: A small study that was clearly data dredging and a foregone conclusion to call kids depressed. They suggest that boys with the highest levels of prenatal exposure to BPA had more symptoms of depression and anxiety than boys with lower levels of prenatal exposure to BPA; no such associations were found in girls.
Caveat comestor, if you are eating up this study.