Eventually it would seem that the father's sperm is going to turn out to be just as important as the mother's egg. Schizophrenia is the most common serious mental illness. A quarter of a million people in Britain have the illness. It affects one person in a hundred at some time in their life, and the rate is the same in every country. Most people are affected when they are in their late teens or early 20s, though it can start at any age.
Schizophrenia is a psychotic disorder.
Symptoms include hallucinations and delusions. Genetic and environmental factors are thought to be responsible. An additional finding in the study was that the longer parents had been married, the more the risk of schizophrenia decreased. But the benefit does not cancel out the risk associated with a father's age. The researchers said further work was now needed to be done to identify exactly why the sperm mutations occur, and how they can be spotted.