Experts made the prediction in a review of the latest research evidence in The Lancet medical journal.
They pointed out that huge increases in life expectancy, amounting to more than 30 years, had been seen in most developed countries during the course of the 20th century.
Death rates in nations with the longest life-spans, such as Japan, Sweden and Spain, suggest that even if health conditions do not improve, three quarters of babies will live to 75.
But assuming that present trends continue, most of those born in well-off parts of the world since 2000 were likely to celebrate their 100th birthdays.
Increases in life expectancy that have occurred since 1840 showed no sign of slowing, said the authors, led by Professor Kaare Christensen from the Danish Ageing Research Centre at the University of Southern Denmark.
“The linear increase in record life expectancy for more than 165 years does not suggest a looming limit to human life-span.
“If life expectancy were approaching a limit, some deceleration of progress would probably occur. Continued progress in the longest living populations suggests that we are not close to a limit, and further rise in life expectancy seems likely,” they wrote.
Mortality among people older than 80 was still falling in rich nations, said the scientists. Data from more than 30 developed countries showed that in 1950 the probability of living from 80 to 90 was 15% for women and 12% for men. In 2002, these figures had risen to 37% and 25% respectively.
Other evidence indicated that people were not only living longer, but managing to preserve their quality of life despite rising rates of chronic illness like cancer. Disability prevalence, as measured by the ability of people to carry out day-to-day activities like dressing and feeding themselves, appeared to be falling.
One series of studies had reported larger improvements in disability-free life expectancy than survival.
Research from Denmark showed that the proportion of individuals who retained their independence was similar among those aged 92-93 and those aged 100. Exceptional longevity did not necessarily lead to exceptional levels of disability.
However, the financial burden of ageing populations containing large numbers of people who do not work was causing concern.
The authors concluded: “Increasing numbers of people at old and very old ages will pose major challenges for healthcare systems. Present evidence, however, suggests that people are not only living longer than they did previously, but also they are living longer with less disability and fewer functional limitations.”