UK - A quarter of British boys and a third of girls born in 2011 will reach 100, according to figures published by the Department for Work and Pensions (DWP).
The figures, based on data from the Office of National Statistics, contrast with men now aged 40, who stand a 13.5% chance of surviving to 100, and women, with a 19.6% chance.
However, even among this group, longevity is increasing. The DWP recorded a 44-day increase in life expectancy last year.
In contrast to previous years, male longevity last year increased faster than female, with an average of 46 days.
According to the pensions ministry's calculations, by 2051, a 65-year-old man in England or Wales could expect to live to just over 90 years and a 65-year-old woman to just under 93 years.
This contrasts with 84.7 for a 65-year-old man and 87.5 for a 65-year-old woman in 2011.
Report author Toby Nutley warned that the data must depend on projected mortality rates and would "tend to be more subjective".
He added: "Whichever method of measurement is used, there has been a large and sustained improvement in expectation of life at all ages in the last century, and this is forecast to continue into the next century."
Separate calculations published by the DWP suggest that 5.4m women will reach state pension age between 2011-12 and 2030-31, and 4.5m between 2016-17 and 2030-31.
However, researchers found that women were falling short in net additional pensions - the occupational component of the state pension.
Using a live course model that factors in education, marriage or partnership, mortality and participation in the labour market, researcher Helen Vincent calculated that 50% of women reaching state pension age up to 2030 would be entitled to a £140 (€159.4) weekly gross state pension.
However, around 2.3m women reaching state pension age between 2016-17 and 2030-31 have less than the £140 entitlement.
Of these women, 1.8m will have had least one child by the age of 40.