Having an older dad might increase a person’s risk of bipolar disorder
The finding is a statistical association drawn from a large population survey. But it falls in line with earlier studies suggesting that children sired by older men face a greater-than-average risk of being stillborn, miscarried or having schizophrenia, cancer or autism.
The theory linking paternal age with an offspring’s health rests on the genetics of aging sperm. Spontaneous mutations can accumulate in the genes of a man’s sperm cells as he ages. These cells divide as many as 660 times by the time a man reaches 40, by some estimates. Each division increases the risk of acquiring a harmful mutation from erroneous gene copying, the theory holds.
Women don’t face this risk since the number of eggs a woman carries is set at birth, each having divi