The rise in divorce is being blamed for an increase in sexually-transmitted infections among the over-50s.
More older men and women are returning to the dating scene, experts say.
But many fail to follow the recommendation to use condoms, assuming medical warnings about safe sex are aimed only at the young.
As a result, rates of diseases such as chlamydia and gonorrhea are increasing among the middle-aged and elderly as well as the young, it is thought.
Between 2002 and 2006, cases of chlamydia among those aged 45 to 64 rose 51 per cent, from 1,276 to 1,933.
Among the over-65s, there was a 37 per cent rise.