Navigating the maze of sunscreens

Dermatologist Dr. Rutledge Forney gives CNN's Rhonda Rowland sunscreen-buying tips.

(CNN) -- When shopping for sunscreen, you have to speak the language. SPF, UVA, UVB, Parsol 1789, zinc oxide, and titanium oxide; What does it all mean?

We asked dermatologist Dr. Rutledge Forney to translate. First things first: SPF stands for "sun protection factor."

"I advise all of my patients for any kid of direct sun exposure in sports or gardening or at the beach to use 30 (SPF) or higher," says Forney.

We need a higher SPF because most of us don't put it on often enough or apply it correctly.

So what's the difference between UVA and UVB? UVB rays burn and thus cause deadly melanoma skin cancer. The higher the SPF rating the more those rays are blocked.

EXTRA INFORMATION Interactive: Skin cancer treatment and prevention

And UVA gives us wrinkles. Ninety-five percent of the sun's rays are UVA. They don't burn, but they do damage the skin. "Of course you want to protect against both," Forney adds.

There's currently no system to tell you how much protection you're getting against UVA rays. But she says, "We know Parsol 1789 is very effective against UVA."

So are zinc and titanium oxide. Zinc oxide sunscreens can be applied as soon as you walk outside. Most sunscreens, on the other hand, need to be slathered on at least 30 minutes before heading outdoors to be most effective.

Especially tricky is getting kids and some men to wear sunscreen. For this, there are dry lotion sunscreens, fast-drying versions, and products packaged to appeal to kids.

Parents are doing a better job at keeping their kids safe from the sun, according to Forney. "We're really finding with teenagers they're not giving me a history of blistering sunburns because parents are really aware of it," she says.

But Forney does have one warning for parents -- keep your kids away from tanning beds. They expose skin to increased UVA levels that have been linked to a less deadly form of skin cancer on the rise in the younger set.

So is there a perfect sunscreen? Yes -- one you like enough to use.