You know that trusty old Teflon skillet you break out for Sunday pancakes? Unlike newer versions, its non-stick coating contains perfluorinated compounds, which have been linked to reproductive problems. Women having trouble getting pregnant are more likely to have high levels of perfluorinated compounds in their blood compared with women who get pregnant the first month they try. And if the women with higher levels do get pregnant, their babies are less likely to meet important development milestones. These compounds were also used in the lining of microwave popcorn bags and products such as Scotchgard. Although manufacturers have been using different formulations for the past few years, perfluorinated compounds don't break down—they're still everywhere, from carpets to couches, so be careful where you sit.
Sources: "Maternal Levels of Perfluorinated Chemicals and Subfecundity," Human Reproduction