Many people wonder if there is a link between infertility and Klinefelter syndrome. While most men with this condition are unable to produce children due to their low sperm count, this is not always the case.

A Summary of Klinefelter Syndrome and Infertility
The vast majority of males with Klinefelter syndrome have fertility issues because they do not produce enough sperm. If these men and their wives wish to become parents, they should seek counseling from their family physician regarding adoption and infertility treatments.
 
Infertility and Klinefelter Syndrome
However, no male with Klinefelter syndrome should automatically assume that he is infertile without further testing. In a very small number of cases, males with Klinefelter syndrome have been able to father children.
 
In addition, a few individuals who believe themselves to be XXY males may actually be XY/XXY mosaics. Along with having cells with the XXY chromosome count, these males may also have cells with the normal XY chromosome count. If the number of XY cells in the testes is great enough, the individual should be able to father children.
 
Karyotyping, the method traditionally used to identify an individual's chromosome count, may sometimes fail to identify XY/XXY mosaics. For this reason, a karyotype should never be used to predict whether an individual will be infertile.