Asked by: Carel Lucas, Perth, Australia
One reason is that men are more prone to heart disease. This may be because women have lower levels of iron since they lose blood through menstruation, or it may be the damaging effects of variations in testosterone in young men. Also men still smoke more than women.
But there may be an underlying evolutionary reason. Like all animals we do not live forever because repairing old cells uses more and more energy as we age, and once we have reproduced our bodies have effectively done their work as far as the genes are concerned.
So keeping an old body going is only worthwhile if it can help the next generation. Mothers’ essential role in bringing up children may mean that their bodies invest more in maintenance than men’s do, and so they live longer, and grandmothers may also be valuable in child care. But in biological terms, old men are disposable.