Klinefelter Syndrome is a condition where a male has the genetic composition XXY. Normally, women have the genetic composition of XX and men have the genetic composition of XY. Males with Klinefelter Syndrome have XXY. This is the most common genetic abnormality in men with infertility. These males are normal except for impaired fertility, and we believe that there are many males who have this condition who do not realize that they have it. A small percentage of affected males will have some sperm in their ejaculate, but most will require a surgery to look for sperm. Before the advent of IVF, these men were believed to be infertile. The optimal management of males with this condition is an area of active research, and the primary goal at this point is to help them preserve their fertility.