It could be something in the cocoa or too much titillation on a favored TV soap: Britain's retirees are shedding their cardigans and getting down to it.
But the men and women who began the sexual revolution as twenty-somethings in the late 1950s are not only finding new passion and partners in their retirement, they are also responsible for a dramatic rise in sexually transmitted diseases.
People living longer and healthier lives, rising divorce rates, the absence of work or family-related stress, even Viagra, may be responsible for the new promiscuity of older people who seem to have missed two decades of public sexual health messages often targeted at the younger, more at-risk groups.
A charity is now calling on the UK government to investigate and to create a new safe sex advertising campaign aimed at older people.
"This should come out of the closet," said Tessa Harding, head of policy at the UK's Help the Aged agency. "I think there's very little public or professional recognition of the sexual health of older people. Its not one of those topics people want to talk about."
In the US last week the Centers for Disease Control (CDC) in Atlanta reported that the incidence of HIV in people aged over 50 is increasing at twice the rate for those younger.
Officials have speculated that a more open society, people entering the dating scene after the monogamy of a marriage and the absence of a fear of pregnancy is causing the alarming rise in sexually transmitted infections.
"The idea that doctors shouldn't approach this question because it might be offensive is really passe," said a CDC spokesman. "If we don't change this predilection in physicians, we're essentially condemning elders with HIV to an early death. That's true more today than ever with the disease management tools we have."
Marcia Ory, chief researcher at the US National Institute on Ageing, and chair of an AIDS and Ageing conference, held last week in Maryland, said: "We can't ignore the older population, and have to understand the role they're playing in the HIV/AIDS epidemic." She said that 10 percent of HIV cases were now in the elderly population.
In the UK, sexually transmitted infections have increased across the board from 624,000 in 1990 to almost one and a quarter million in 1999 -- the most recent figures.
While in the whole population rates of gonorrhea and syphilis have increased by 55 percent since 1995, in the 65-plus age group the rise is more than 300 percent.
But the rise could possibly mean that the stigma of attending an STD clinic is eroding, according to veteran British agony aunt and social campaigner Claire Rayner.
"Years ago an older man who caught a dose of the clap from a prostitute would not be contacting his doctor. People were stoical and not over keen to present themselves for treatment but now more people are prepared to seek help.
"People do insist in thinking that older people are asexual. Believe me they are not, they have been having a randy time for a long time," Rayner said.
The Department of Health is now compiling a new strategy for tackling the STD issue across the board, said a spokeswoman.