Q. Ever since my son was born, I have been asking my husband's family not to smoke around him  -- but they don't seem to care about anything but their addiction. They think that standing by a window with their cigarettes is effort enough. It makes me so angry! What can I do?

A. You are absolutely right to protect your child from secondhand smoke and, likewise, to educate your in-laws  -- you're being an appropriately-protective mother. Although standing by the window does show some consideration and somewhat reduces the effects of secondhand smoke on your child, the smoke still accumulates on his clothing and in his hair. That's why even nonsmoking areas in restaurants are not enough. It's as impossible as trying to chlorinate half a swimming pool  -- the chemical will still dissipate into everything. Here's how I explain the hazards of smoking to parents and grandparents who otherwise may not get the point: "Suppose you are about to take your child into a room when you notice a sign that reads: 'Warning! This room contains poisonous gases from about 4,000 chemicals, some of which have been linked to cancer, lung damage, and SIDS. These chemicals are especially harmful to the growing breathing passages of young infants and children.' You certainly wouldn't want to take your baby into this room! But it's these chemicals you'd be exposing your child to if you brought him into a room of cigarette smokers." In a nutshell, smoking and children don't mix. Here's why: Smoking makes children sick. Children who are exposed to cigarette smoke are more likely to get pneumonia, asthma, ear infections, sinus infections, bronchitis, eye irritation, and croup. Children whose parents smoke visit the doctor two to three times more often than children of nonsmoking parents, because of respiratory infections and allergy-related respiratory illnesses. Even more worrisome, the risk of a baby dying from SIDS is seven times higher if a mother smokes. Smoking bothers little breathers. The passages through which air travels to the lungs are lined with tiny hair-like filaments, called cilia. Their job is to sweep away mucus from the airways and help keep them open. Smoke paralyzes the cilia, so they can't move and can't do their job. This makes congestion due to colds and allergies much worse. Smoking hurts little hearts. Besides being hard on a child's lungs and breathing passages, smoking may harm growing hearts. Levels of HDL (so-called "good cholesterol") are lower in children who are around people who smoke, and lower HDL levels are associated with a higher risk of heart disease. Smoking injures little brains. Nicotine can be a neurotoxin. Researchers who have studied why the incidence of SIDS is greater in infants exposed to cigarette smoke believe that the developing brain center that controls breathing suffers from oxygen deprivation and, perhaps, damage from neurotoxic chemicals. Here is a trick that has worked for many families in your situation: Use your child to appeal to his family members. If he hasn't already learned about the health hazards of smoking in school, use the above information to draw pictures for him showing how smoke damages the lungs and causes people to die early. Your child will probably then start talking to your in-laws about the hazards of smoking in a compelling, but childlike manner: "Grandma and Grandpa, I don't want you to die early because of cigarettes," or "Aunt Jane, don't you know those things will rot your lungs?" Sometimes it takes wisdom out of the mouths of babes to get adults to kick their harmful habits. While this is a hot-button issue for you, try to take a loving approach as you share your dilemma with your in-laws. Tell them you want your child to be around them more often because it's good for your child and good for them  -- "your doctor" has impressed upon you that children should never be around secondhand smoke, and as a caring mother you want to abide by this. That's the best you can do, and the rest is up to them.