Yes, but it depends more on what you grill than how you grill it.
The problem with grilling any kind of protein - red meat, poultry, fish - is that the process causes formation of two cancer-causing agents: HCAs, or heterocyclic amines, and PAHs, polycyclic aromatic hydrocarbons, said Karen Collins, nutrition adviser to the American Institute for Cancer Research. Laboratory data show these substances trigger the cancer process, and while data in humans are limited, there is suggestive evidence that they can also trigger cancer in people.
Happily, grilling vegetables produces no HCAs or PAHs, nor does grilling fruit. Formation of the nasty chemicals also seems to be reduced if you marinate meat, even briefly, before grilling, though it's unclear why this would be.
Reducing the temperature also helps reduce the risk (grill, don't char) and cut away fat before grilling because fat dripping down onto the grill causes smoke, which contains PAHs.
But it's also important to take this advice with a grain of salt. It's fine to grill meat, even red meat, once a week or so during cookout season, said Dr. George Blackburn, a nutritionist at Beth Israel Deaconess Medical Center and associate director of the Division of Nutrition at Harvard Medical School.
As usual, it's a question of moderation. As Blackburn put it, "We don't want to ruin the joy of family get-togethers."
E-mail health questions to email@example.com.