Karyotype for men can help us identify, it isn’t common but it is an important cause if there is no sperm in the ejaculate it’s one of the reasons why we do a karyotype in that situation. It’s not strictly speaking karyotype but slightly more detailed tests on the Y chromosome which is the chromosome that carries the genes responsible for normal sperm production. So a specific Y chromosome micro-deletion test can also help pick out some genetic causes for the lack of sperm production. Another genetic test that might be useful is cystic fibrosis testing in men. For women karyotype is much less commonly done and the scenario in which I can think it would be useful, would be where someone is suspected of having Turner’s syndrome where the ovaries don’t develop properly and usually the woman doesn’t start to menstruate until quite late or not at all and that is how this comes to light.
