A tan is the body's natural protection against sunburn. Your skin is designed to tan as a natural body function, and the body is designed to repair sun damage as a natural process.
Indoor tanning, for individuals who can tan, is an intelligent way to minimize the risk of contracting sunburn while maximizing the enjoyment and benefit of having a tan.
There is no doubt that overexposure to the ultra-violet light carries risks. Generally, the lighter your untanned skin is, the greater those risks may be.
The photobiology research community has determined that most skin cancers are related to a strong pattern of intermittent exposure to ultraviolet light in those people who are genetically predisposed to skin cancer, and not simply to cumulative exposure. That again suggests that heredity and a pattern of repeated sun burning is what we need to prevent. And that kind of prevention is what the indoor tanning industry is doing effectively.