Day camp and beach vacations make summer an outdoor go-go season for many kids, but the amount of UV radiation they soak up may determine their risk of skin cancer as adults.

Recent studies suggest 80 percent of lifetime sun exposure occurs before age 18, says Raquel Hernandez, a pediatrician at Johns Hopkins Harriet Lane Clinic in Baltimore.

That accumulated exposure is linked to skin cancer and premature aging (in the form of wrinkles and leathery skin) and eye damage. Just one blistering sunburn in childhood can increase a child's risk of developing melanoma by up to 50 percent, she adds.

Sunscreen of at least SPF 30 is an important ally in protecting young skin against the sun's damaging effects.

But experts say you can do more to protect young skin. Covering children's skin with clothing protects better than any sunscreen can, says Stanley Miller, a dermatologist at Johns Hopkins Medical Center.

He recommends keeping kids (and adults) in the shade between 10 a.m. and 4 p.m., when the sun's ultraviolet radiation is strongest, dressing them in dark clothes with a tight weave and encouraging them to wear sunglasses and a wide-brimmed hat of at least four inches. (Good luck!)

Some companies such as Lands' End and Solumbra have created lightweight clothing with built-in sun protection designed to last through washings.

Not all doctors see great value in wearing treated fabric of this kind, but Miller says he is "a big fan of this clothing," which he says does "a better job of blocking out the sun since you don't have to worry about sweating or reapplying it like sunscreen. And they are making it much more hip-looking."