The guest was Devra Davis, Director of the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute, and author of The Secret History of the War on Cancer.
One of the callers asked about putting sunscreen on children. First Ms. Davis pointed out that one concern about always using sunscreen is that you might deprive kids (or adults) of their needed 20 minutes of sun exposure a day (which allows us to produce the Vitamin D we need). Then she went on to address the caller's concern that some products are carcinogenic in and of themselves, offering more risk exposure than no sunscreen at all. She said that some products are safer than others, but since she didn't really have time to go into it, she recommended people go to EWG.org, to find out more information about toxics in consumer products and to figure out what is safer to use with your kids.
I just wanted to pass that along.