OLDER people should be grateful they’re still around – because there’s no obvious evolutionary need to live beyond the age of 50, say scientists.

Men’s ability to father children later in life is not the reason why they can survive into their 90s and even beyond.

Likewise women lasting past the menopause serves no obvious purpose.

The discovery disputes the “grandmother hypothesis”

that offers an explanation for why humans live so long after the end of their reproductive age.

According to the theory, elders contribute to the fitness of younger individuals by caring for grandchildren and handing down i mp o r t a nt c u l t u r a l knowledge.

But the latest findings suggest the scientific explanation for human longevity, which has been debated for decades, remains a mystery.

Dr Jacob Moorad, of Edinburgh University’s School of Biological Sciences, said: “Why we live beyond 50 has long puzzled scientists. There are no obvious evolutionary benefits to genes that promote living in infertile individuals.

“We were surprised to find that fertility has little genetic link to male longevity and puzzled we are no closer to explaining why women live far beyond menopause.”

The study published in Nature Ecology and Evolution said the riddle is even more complex than previously thought, with insight into our 50-plus lifespan still evolving