While Westerners consider tanned skin healthy and attractive, most Chinese think a fair complexion is more desirable.

Many Chinese women try to avoid ultraviolet exposure as much as possible, and use a lot of whitening products.

Tu thinks that is unwise.

Beijing resident Chen Yingshu, for instance, wears sunscreen in all seasons, no matter whether it is sunny or raining, and she rarely goes without her umbrella in summer.

It takes her half an hour to remove her sunscreen and make-up, but she thinks it's worth the effort because she says her skin looks tighter, fairer and younger, compared with her peers.

Experts say she is actually increasing her risk of getting skin cancers.

"The whiter the skin is, the more vulnerable it will be to skin cancers," Tu says.

For those who grew up in areas that are exposed to strong sunshine, being in the sun is part of life.

Yin Chao is a writer now living in Beijing, but he grew up in Dehong Dai and Jingpo autonomous prefecture in Yunnan province. It is a place where the sun shines strongly almost every day of the year.

Yin says he is amused to see how people from Beijing go overboard in hiding from the sun.

"Women always wear sun lotion and use umbrellas, and even men use sunscreen, too," Yin observes. "That is absurd to me. A man doesn't need to look fair-skinned."

At home, he says, only women use sunscreen. He himself is happy to go unprotected, even years after he came to Beijing.

"My skin is always as red as a shrimp in summer," Yin says. "I never use sunscreen, and I don't wear sunglasses, either."

Generally, ultraviolet-A is the major cause of skin tanning and aging, and ultraviolet-B is responsible for blisters and cancers. Because darker skin has a stronger ability to reflect and absorb ultraviolet rays, the tanning process is actually a natural defensive mechanism the skin uses to protect itself from skin cancers, Tu explains.

"Sunlight helps the body produce vitamin D needed to better absorb calcium and to produce chemicals that fight depression," he says.

"The human body needs sunlight. It is not necessary to stay out of the sun all day."

In summer, when ultraviolet rays are stronger, normal, everyday clothes are protection enough against harmful ultraviolet-B radiation. For limbs, the face and hair, an umbrella and a hat may help.

But even so, the experts themselves have differing opinions. For example, Wang Xin, director of the dermatology department of Tsinghua University No 1 Hospital, does not agree completely with what Tu says.

"Ultraviolet A and B are man-created concepts. In nature, there is no such clear-cut division," Wang says. "Just as there is no evidence to show ultraviolet-A directly causes skin cancers, there is also no evidence that ultraviolet-A does not cause them either."

He suggests people wear protective clothing in ultraviolet-saturated environments, such as in summer and on the beach.

He also says that it is unnecessary to bleach the skin with chemical products.

Contact the writer at [email protected].