More reason to do regular skin checks: Melanoma rates in young women have skyrocketed. A Mayo Clinic study finds they've increased eightfold between 1970 and 2009. (Show a derm any new or changing moles.) These are some potential causes of skin cancer:
A Family History
If your mother, father, siblings, or children have had a melanoma, your risk is 50 percent greater than the average person's. If more distant relatives—like grandparents or cousins—have been diagnosed, your risk goes up, but not as much.
A Blistering Sunburn
Just one in childhood or adolescence more than doubles your chances of developing melanoma later in life. And even five mild sunburns over the course of your life can also double the risk.
Indoor tanners—both past and present—are 74 percent more likely to develop melanoma than those who have never used a tanning bed. They also have a 69 percent increased risk for early-onset basal cell carcinoma.
Fair Skin or Light Eyes
Pale women have less melanin, the skin's natural sun protection. Those with baby-blue or green eyes are also more prone to skin cancer, especially ocular and eyelid melanomas, than women with deep-brown irises.
Living in a Sunny or High-Altitude Area
Tropical climates expose you to strong UV radiation year-round, says Fields. As for altitude, for every 1,000 feet above sea level, you increase your UV exposure by 4 to 5 percent.