People who want to live longer should avoid having sex, according to Sheffield University experts, explaining why nuns tend to live to old age.
Scientists at the University of Sheffield say refraining from having sex will help you live longer than all of your peers.
And experts believe it could explain why nuns - who stay away from the act completely - tend to live longer.
Researchers discovered that mealworm beetles live for longer if they avoid mating, while those who tried to produce offspring each day passed away at a much younger age.
Mating was found to release a hormone in the insects needed to produce sperm in a male or eggs in a female.
But this was also found to have a negative effect on their immune system, the researchers found.
This makes them vulnerable to potentially deadly infections as their body's natural ability to fight rogue bacteria is compromised.
Despite the mechanism not being the same in humans, study author Dr Michael Siva-Jothey believes the principle can be applied.
He said: 'Nuns tend to have a longer lifespan than women with children and most people know of someone with a maiden aunt who seems to live forever.
'The question is, why? The beetles which mate die sooner than the beetles which don't mate.'
Humans also have weaker immune systems during sex, which explains how STIs can be easily spread, he added.
Nuns, priests, vicars and monks are known to live longer than others - but not for their religious protection.
It is believed their low rates of high blood pressure - which increases the risk of heart disease and stroke - are responsible.
This comes after research last week revealed that people who eat hot chilli peppers were 13 per cent less likely to die early.
Vermont University scientists found that capsaicin - responsible for the fiery kick - seemed to ward off heart conditions and stroke.
While in August, experts from Massachussetts General Hospital found going vegan could add years to someone's life.
Eating less protein from animal sources and instead swapping it for cereals, beans and soya substantially reduced death rates, they discovered.
Mortality from heart disease fell 12 per cent, and deaths from all causes were reduced by 10 per cent.