Klinefelter’s syndrome is a condition in which men have an extra X chromosome in most of their cells – an XXY pattern instead of the normal XY pattern that most men have. Boys with the XXY-condition tend to have language problems and lesser muscle tone than other boys, and they tend to have trouble fitting in. But as adults, most of them lead normal, successful lives.

Learn more about this condition from experts, meet others who have it, and network with them by joining our online support group for people with Klinefelters’ syndrome.