People with older fathers could live longer

Leaving fatherhood until later in life can help people to live longer.

This is according to a group of US scientists who claim that children with older fathers appear to be "genetically programmed" to live well into old age.

The work, which appears in the Proceedings of National Academy of Sciences journal, claims that the genetic make-up of sperm alters as a man gets older and a DNA code which encourages longer life is developed.

It also claims that this trait is then passed on to their children.

Lifespan has long been linked to the length of structures known as telomeres that sit in the chromosomes which host DNA. In general terms, the shorter the length of telomeres, the less time the person is likely to live.

Telomeres shorten with age, but the scientists found that in sperm they actually lengthen as the person gets older.

And because a man's DNA passes to their child through their sperm, these longer telomeres can be inherited also.

Dr Dan Eisenberg and colleagues from the Department of Anthropology at Northwestern University explained:  "As paternal ancestors delay reproduction, longer telomere length will be passed to offspring, which could allow life span to be extended as populations survive to reproduce at older ages."

Despite this, professor Thomas Von Zglinick, from Newcastle University, said that more research is needed before people can start thinking that just because their father was older than the norm when they were conceived, they will live longer.

"Very few of the studies that linked telomere length to health in late life have studied the impact, if any, of paternal age," he told the BBC.

"It is still completely unclear whether telomere length at conception (or birth) or rate of telomere loss with age is more important for age-related morbidity and mortality risk in humans.

"The authors did not examine health status in the first generation offspring."