PFOA and PFOS — chemicals that are used in nonstick pans, waterproof products, and firefighting foam — reduce male fertility.

The study was done on men exposed to those chemicals through industrial pollution. Whether contact with consumer products could give people a big enough dose to have an effect is apparently not clear.

A moderate reduction of human fertility is a change for the better, for the next few decades, but since these chemicals never degrade they could accumulate ever-larger quantities.