Dear Dr. Scott: My son just turned 1 year old. In a few months his pediatrician wants to give him the MMR vaccine. I've heard reports that this vaccine can cause autism. Should I be worried?

    -- Elaine B., San Francisco

    The MMR vaccine immunizes against measles, mumps, and rubella -- all transmissible and potentially deadly diseases. It's standard pediatric practice to administer two doses of the vaccine, one at 15 months and the second between the ages of 4 and 6 years old. The prospective tie between the vaccine and autism -- a disorder affecting social development -- gained notoriety after the publication of two reports by the same author citing a correlation. These reports were flawed, and other researchers have not been able to replicate the results. In fact, several well-designed and controlled studies published in reputable, peer-reviewed journals find no association between the vaccine and autism. By these accounts, autism is considered a genetic disease. So I'd suggest you follow your pediatrician's recommendations in order to avoid putting your child at unnecessary risk.

    Dear Dr. Scott: My 52-year-old mother recently fell and broke her hip. She suffers from osteoporosis. I've heard that it's a hereditary disease, and that it can be worsened by pregnancy and breastfeeding. I want to have children, but I also want to avoid the problems my mom is going through. Any thoughts?

    -- Libby M., Belmont

    Osteoporosis affects about 28 million Americans. It is a chronic, progressive disease resulting in bone loss and an increase risk for fractures, particularly of the hip and spine. About 10 percent to 20 percent of those patients who break a hip die within a year of the fracture, and another 50 percent are permanently disabled and require assistance to walk. We don't know the exact cause of the disease, but some of the major risk factors include age, heredity, poor nutrition, sedentary lifestyle and smoking. It's true that during pregnancy and breastfeeding bone loss occurs, but typically the mother's bone density returns to normal about six months after breastfeeding ends. In fact, studies show that the more children a woman has, the more likely she is not to develop osteoporosis. Therefore, I wouldn't worry about a connection between pregnancy, breastfeeding and the disease. Rather, you should ensure that you're eating right, including taking plenty of calcium, and getting exercise. Of course, anyone planning to get pregnant should consult an obstetrician.