"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."
If the rapid rise continues for men, Prof Mayhew believes they will soon live longer than their female counterparts.
Men have traditionally drawn the shorter straw in terms of life expectancy, with boys more likely than girls to die before birth and women continuing to outlive men as adults.
But that may be about to change, according to Prof Mayhew's study.
One of the main reasons could be men veering toward healthier lifestyles, once largely the domain of females.
"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 more males than females," Prof Mayhew told the Sunday Times.
"Men are getting a bit better behaved and women are adopting male life expectancies," Professor David Leon, from the London School of Hygiene and Tropical Medicine, told the BBC.
Prof Mayhew's study was carried out in England and Wales.
The study only took into account people aged 30, and Prof Mayhew is quick to point out a boy and a girl born on the same day will not have the same life expectancies and that boys are still more likely to die in sporting and road accidents.
No such study has been carried out in New Zealand, with current statistics showing life expectancy still favours females.
The last report indicated life expectancy at birth was 78.4 years for males and 82.4 years for females.
