"The concern is exposure to this chemical that we're all exposed to could increase the risk of miscarriages and the risk of babies born with birth defects like Down Syndrome," says Hunt. "The really stunning thing about the effect is we're dosing grandma, it's crossing the placenta and hitting her developing fetus, and if that fetus is a female, it's changing the likelihood that that female is going to ovulate normal eggs. It's a three-for-one hit."