Klinefelter Syndrome

By |2015-07-27T17:10:06+00:00July 27th, 2015|Categories: Genetics|Tags: , , , |4 Comments

Klinefelter Syndrome

Genetics play a big role in fertility. Men generally have a “XY” chromosomal makeup (women are “XX”). However, occasionally boys are born with an extra X chromosome in their genetic makeup – “XXY”, or “47,XXY”. This condition is known as Klinefelter Syndrome, and it has been shown to drastically reduce the man’s fertility.


Roughly 1 out of every 1,000 boys is born with the extra X chromosome which leads to Klinefelter Syndrome. This condition is a fairly common cause of infertility, accounting for 5-10% of all cases of oligospermia and azoospermia.


Increasingly, this condition can be detected with prenatal diagnostic technologies. There are usually no outward signs of Klinefelter Syndrome in pre-pubescent males. It is usually diagnosed during puberty or in adulthood, and infertility is actually one of the leading symptoms. The main clinical signs of the condition include:

  • Infertilty
  • Small, firm testes
  • Hypogonadism
  • Gynecomastia
  • Tall, slender body with long legs and short torso.
  • Osteoporosis (middle-age or earlier)
  • Motor delay or dysfunction
  • Speech challenges
  • Attention difficulties
  • Learning disabilities


Men with Klinefelter Syndrome almost always have hypogonadism – meaning they are unable to produce normal levels of testosterone. This leads to a drastic reduction in sperm count and causes most men with the condition to be infertile.

Think this may be you?

See a doctor. Klinefelter Syndrome is usually diagnosed by evaluating the outward symptoms (e.g. small testes, tall/slender build, and low testosterone), and confirmed by analyzing the chromosomes in white blood cells. If you are truly not producing sperm in your ejaculate, fertility specialists can still harvest your sperm and achieve pregnancy with increasing success using amazing advancements in reproductive technologies.


1. D.J. Wattendorf and M. Muenke. “Klinefelter Syndrome” American Family Physician, 2005 72(11): 2259-2262

2. J.L. Simpson, J.M. Graham, C. Samango-Sprouse, R. Swerdloff. “Klinefelter syndrome.” In: “.B. Cassidy and J.E. Allanson. “Management of genetic syndromes” 2d ed. Hoboken, NJ: Wiley & Sons, 2005: 323-8.

Sara SDx

Sara SDx

Editor of Don't Cook your Balls, Co-Founder of TrakFertility.com, Health Coach and Men's Health Advocate. Passionate about sperm, men's health and helping people build their families.


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