The gap between male and female life expectancy is closing and men could catch up by 2030, according to an adviser for the Office for National Statistics.
Prof Les Mayhew said the difference between the sexes peaked at nearly six years in the 1970s.
Life expectancy is going up all round, but the rates for men are increasing faster.
Plummeting smoking rates in men are thought to explain a lot of the change.
Prof Mayhew, a professor of statistics at Cass Business School, analysed life expectancy data in England and Wales. He was working out how long 30-year-olds could expect to live.
His findings show men languishing far behind for decades, but now starting to get closer to women. If current trends continue, Prof Mayhew predicts, both sexes could, on average, be living to the age of 87 in 2030.
He said: "What's interesting at the moment is that in the last 20 years or so, male life expectancy at 30 has jumped by about six years and if it jumps by the same amount in the next 20 years it will converge with female life expectancy."
The reason could be down to men living a healthier lifestyle. "One of the main reasons, I think, is the trend in the prevalence of smoking. Smoking took off after 1920 in the male population and at its high about 80% of males smoked.
"This was reflected in more divergence in the life expectancy, so by the time you get to about 1970 it was at its peak - the difference in life expectancy was about 5.7 years."
Other factors are thought to be safer, more office-based, jobs. Millions of men used to work in hazardous occupations such as coal mining. Healthcare has meant more men live longer as well. People with heart disease, which is more common in men, can expect to live much longer than they did a few decades ago.
By contrast, women started smoking later than men. undefined , but are falling fast in men.
A boy and a girl born on the same day will still not have the same life expectancies, as the study looked only at people who had already reached 30. Boys are more likely to die in their first year of life and are more likely to take up dangerous sports or be involved in fatal accidents.
It means that women could still have the edge for some time to come.
Prof David Leon, from the London School of Hygiene and Tropical Medicine, said: "In virtually all countries in the world, women do have a slight advantage."
However, he said the gap was definitely closing in some countries.
Countries with lower levels of life expectancy, such as in sub-Saharan Africa, showed very little difference between the genders. This was due to the prevalence of infectious diseases which "are not picky about men and women", he said.
In countries that had defeated most infectious diseases, such as in Eastern Europe, "there is a much bigger difference, mostly dominated by lifestyle factors".
At one point in the 1990s, the gap between life expectancies in Russia reached 13 years. Prof Leon said it was an "absolutely massive" difference in a "very gendered society".
In his third class of countries, such as the UK, the gap in life expectancies is starting to narrow.
He said: "Men are getting a bit better behaved and women are adopting male life expectancies."