They tend to produce allergic reactions more frequently than physical ultraviolet light blockers. If allergies are a concern, physical sun blocks such as zinc oxide, talc or titanium dioxide provide good coverage, are waterproof, and most importantly, cause fewer allergic or photoallergic reactions. Zinc oxide is recommended for the sensitive areas of a baby's skin such as the nose and below the eyes. These products are not absorbed by the skin and tend to create a mask-like appearance. Padimate O is an important ingredient to look for because it remains in the skin for a few days after application, providing extra protection.
Esters are usually non-staining and cosmetically easier to work with than other chemical absorbers.
For children, she recommended Water Babies and Children's PreSun 29 as good products. Active are safe products for acne sufferers. No matter what, sunscreen should be reapplied to insure effectiveness. If swimming, sunscreen should be waterproof. Just protect yourself and know what you're getting when you buy your sunscreen.