Two genetic factors lead to infertility as such. The very good example is Turner syndrome where one X chromosome is missing and the ovaries don’t develop well and the woman either has very few eggs or no eggs. So that is obviously quite a severe cause of infertility and that has a clear genetic link. In men, there is the condition of cystic fibrosis and men with cystic fibrosis often don’t have what’s called the vas deferens -it is a duct that is or a tube that is involved in sperm transport and that is missing. So, that’s a mechanical cause of sperm not being present in the ejaculate. Beyond that there are very few genetic conditions that directly lead to infertility. Although there are conditions that can run in families that have a partly genetic, partly environmental basis such as Polycystic Ovary Syndrome and endometriosis and of course those can cause infertility.
