After having kids, I started looking at all the ingredients that go into the products they come in contact with (mainly soaps, lotions, etc), to make sure I was minimizing any potential long term impact to their health. Cancer runs in both my family and Steve's so we will do anything we can to reduce risks for our kids since they are likely pre-disposed.
The Environmental Working Group puts out a report every year on Safe Sunscreens. I only buy off this list..
Elsewhere in the Environmental Working Group's website is a section called Skin Deep which lists safety of a lot more personal products (make-up, shampoo, lotions, etc). Take a look, it's very informative.
Have a safe and sunburn free summer!