Why the Xs Have It

Though women sometimes complain about their sexual lot in life, in many ways, it's good to be a girl. Girls in the United States have a 20 percent lower mortality rate than boys, do better in school, and are more likely to go to college. And it turns out that women — because of their two X chromosomes — are less susceptible than men to some diseases. After decades of research on X chromosome-linked diseases, and with a new book on the subject coming out this fall, Johns Hopkins School of Medicine researcher Barbara Migeon is getting the word out to doctors that X chromosomes are the key to many sex differences in health. "The response from my physician colleagues has been tremendous," Migeon says. "They're both surprised and interested."Most doctors, Migeon says, attribute "women's diseases" to female reproductive organs and hormones. But many common diseases that have little to do with reproductive organs — like meningitis or heart disease — are expressed differently in men and women. When studying the sex differences in many diseases, Migeon says, "many doctors really haven't made the leap to a genetic component."Read more at...Johns Hopkins Magazine, June 2006.