Genetics Home > Can Females Have Klinefelter Syndrome?
Can females have Klinefelter syndrome? The answer is no. Females cannot have Klinefelter syndrome -- they do not have a Y chromosome (one of the chromosomes responsible for male sexual development). However, although females cannot have Klinefelter syndrome, they can develop a genetic problem with their sex chromosomes known as Turner syndrome.
Females cannot have Klinefelter syndrome because they do not have a Y sex chromosome. The answer to this question is best understood by first understanding the sex chromosomes.
Chromosomes, the spaghetti-like strands of hereditary material found in each cell of the body, determine such characteristics as the color of our eyes and hair, our height, and whether we are male or female.
In humans, there are 23 pairs of chromosomes in our cells. Each cell contains 22 pairs of chromosomes that are the same in males and females (these are called autosomes). The remaining pair of chromosomes, the X and Y chromosomes, are not shaped similarly, and thus are not matched in the same way as the autosomes.
The X and Y chromosomes are called sex chromosomes. They are responsible for the differences in development between males and females. A Y chromosome contains genes responsible for the development of testes, and the presence of an X chromosome paired with a Y chromosome determines male development. On the other hand, two X chromosomes are required for normal ovarian development in females.
The cause of Klinefelter syndrome is the presence of one or more extra copies of the X chromosome in a male's cells. Extra copies of genes on the X chromosome interfere with male sexual development, preventing the testicles from functioning normally. This interference also reduces the levels of testosterone in the body.
Most often, the cause of Klinefelter syndrome is a single extra copy of the X chromosome, for a total of 47 chromosomes per cell. Males normally have one X chromosome and one Y chromosome in each cell (46,XY), but males with Klinefelter syndrome have two X chromosomes and one Y chromosome (47,XXY). Females normally have two X chromosomes (46,XX).