I recently learned that combining sunscreen and bug repellent can be harmful to children. What? We live in southeast Texas where everyone needs protection from bugs and sun. This article explains the problem. I can't believe I've never heard this before.
Insect repellent should be applied one time a day while sunscreen should be applied often. Most parents reapply insect repellent too frequently. There are also studies which show that sunscreen might actually cause several times more DEET to be absorbed into the blood.