Researchers say men will soon live longer than women for the first time since records began after abandoning their unhealthy, macho lifestyles.
Once boys born in 2000 reach the age of 30, they can expect to match girls of the same age by living to 87.1.
Researchers predict younger males will then go on to surpass the life spans of their female counterparts.
In 1970, a man aged 30 was expected to die 5.7 years before a woman of the same age – the widest gap since records began in 1841.
The common view has been that men are condemned to earlier graves by underlying genetic factors – despite growing life expectancies for both sexes.
Leslie Mayhew, professor of statistics at Cass Business School at London’s City University – which advises the Office of National Statistics (ONS) on population projections – points to lifestyle changes to explain his controversial forecast.
Prof. Leslie Mayhew told The Sunday Times: “There has been a huge decline in the numbers working in heavy industry; far fewer males smoke than before, and there is much better treatment for heart disease, which tends to affect males more than females.”
Lung cancer rates have also halved among men since 1975, while nearly doubling among women.
Leslie Mayhew’s predictions – which exclude Scotland, where men are expected to continue to trail women because of lifestyle factors – are due to be published next month.
But the forecast does not match that of the ONS, which predicts a boy born in the millennium year who reaches 30 can expect to die 3.5 years before a girl of the same age.
Prof. Leslie Mayhew argues the ONS has been consistently too cautious in acknowledging the shifts in life expectancy over the past few decades.
The longer longevity for men only kicks in at 30, with life expectancy remaining much better for baby girls and mortality rates higher among men between their reckless years of 16 and 30.
The research also highlights discrepancies between men and women in other countries, such as Russia, where there is a 12 year gap, and India, where it is just 12 months or less.
The report also predicts that the gap will close in Sweden in 2024 – six years ahead of Britain – but not until 2046 in France.