Eggs get old. This is old news and it’s why many an eyebrow is raised at the idea of a woman leaving childbearing to the post-35-years ‘danger zone’ of advanced maternal age. But ageing isn’t just something that affects a woman and her eggs. Men may be able to keep churning out sperm well into their dotage, but research is revealing that quality can suffer. As a man ages, the number of new — or ‘de novo‘ — mutations introduced into his sperm increases. The result is what’s known as the paternal age effect, where certain conditions, such as autism and schizophrenia, are more common in children of older men.