Having Klinefelter SyndromeA common concern for males with KS and their families is the ability to father children. Although subfertility is characteristic of KS and the majority of KS men do not have sperm in the ejaculate, there are exceptions as well as other techniques to help with fertility potential. Although small, firm testes are common among all KS men, up to 50% have normal testosterone concentrations. Men with the mosaic form of KS (having 46XY cells mixed with 47XXY cells) are occasionally fertile. KS men with low sperm counts in the semen may have the sperm used for assisted reproductive techniques (such as in vitro fertilization- IVF) by simply collecting the sperm through semen samples obtained by masturbation.
There is no therapy to improve sperm production in KS, but sperm can be harvested surgically from the testicle, and success rates of harvesting sperm are as high as 69% in the hands of surgeons with microsurgical expertise. This sperm can then be cryopreserved (frozen) for future use or used at the time of harvest in combination with IVF with intracytoplasmic sperm injection (ICSI-injecting one sperm into one egg to facilitate fertilization prior to transferring the embryo to the uterus) for the best odds of achieving a pregnancy. Concern of transmitting KS to the offspring is common and although there is a slight increase in chromosome abnormalities in the sperm of men with KS, only one case of a 47XXY fetus being conceived by the sperm of a KS father has been reported thus far.
Importantly, KS men who are interested in fertility potential should not be placed on testosterone replacement, as this will decrease or even shut down the testicles ability to produce sperm. If men are on testosterone long enough, this can be a permanent effect. Other medications such as aromatase inhibitors or HCG can be used to increase testosterone levels, if they are low, and maintain the man’s level of sperm production potential. There are still plenty of gaps in our knowledge and there is much to learn, but we do know that there is hope for KS men to father children.
Parviz K. Kavoussi, M.D.