Klinefelter Syndrome is something many women (and men) don't know about and they should -- if having children with their spouse is important to them, if they have a son, and to understand why diagnosis is important for a variety of reasons.
Men are born with an X chromosome from their mothers and a Y chromosome from their fathers. Those born with KS inherit an extra X chromosome from their mothers so instead of being a normal XY male, they are an XXY male.
KS is sometimes called 47 XXY since people normally have 46 chromosomes and are XY only.
There's no way to avoid having a child with this syndrome as there does not appear to be a genetic link. However, older mothers (over the age of 35) are more likely to have a son with this syndrome.
Many men with this syndrome (about one in every one thousand men are born with it) don't have any symptoms at all but those that do tend to adopt physical traits seen in females. This includes breast development (and an increased risk for breast cancer), wider hips, less body hair and smaller than average male genitals.
Another aspect of KS that is often seen is learning disabilities and difficulties with socialization as well as lowered sex drive or possible sexual dysfunction.
KS can also cause infertility in males and is one of the leading causes of infertility in males. For some men, a diagnosis only comes when they cannot have children and are tested for infertility.
Other ways to diagnose are:
Taking a test called a karyotype. In the case of KS, there are usually 47 chromosomes rather than the normal 46.
Many men with XXY do not know they have the condition. The diagnosis may be found:
• When amniocentesis is done
• In babies— undescended testes or very small penis
• In children—when the child is having problems learning
• In adolescents—when the child has excessive breast development
There are various treatments for males with KS. The main one is testosterone shots that increase "maleness" in men with KS, including increased strength, body hair and sexual performance. Men with KS can also receive speech and language therapy.