Substantial majorities of people who are married or who have a partner remain sexually active throughout the second half of their lives, according to a survey of 27,500 people aged 40 to 80 in 29 countries.
"There was very little effect of age on sexual well-being," though other factors such as health problems or depression had a substantial impact, said lead researcher Edward Laumann of the University of Chicago in a telephone interview.
The survey published in the Archives of Sexual Behavior looked at how they viewed their sex lives, their health, and their happiness.
It found that a greater proportion of people in Europe, North America, and Australia, where men and women have more or less equal relations, enjoyed sex physically and emotionally, Laumann said.
A smaller percentage of people reported satisfying sex lives in male-dominated cultures in poorer countries, the research showed.
But the gender gap persisted around the world.
"There's a systematic disparity between men and women, where men are on the average substantially - or about 10 points - higher in their levels of satisfaction as women in that country," he said.
Most of those surveyed at random were married, though there was an obvious bias toward participants who were willing to talk about sex, and toward urban populations in less-developed nations.
"Pleasure is not part of the story" in sexually conservative cultures in the Far East - China, Indonesia, Japan, Taiwan, and Thailand, Laumann said. "Procreation is the rationale for sex. Many women ... characterize sex as dirty, as a duty, something they endure" -- and often stop having it after age 50.
But roughly two-thirds of adults in Western nations reported their sex lives were very to extremely satisfying - though some countries appeared happier than others.
Roughly four out of five middle-aged to older Austrians, for instance, rated their sex lives highly, while considerably fewer adults in France and Sweden shared that sentiment.
In the United States, about three-quarters of men and two-thirds of women reported they were very satisfied with the physical and emotional aspects of their sex lives.
In Japan, by contrast, just 18 percent of the men and 10 percent of the women answered positively about their sex lives. And in Taiwan, only 7 percent of the women said sex was very important in their lives.
Satisfying sex is not the same as a satisfying sexual relationship, Laumann said the survey showed.
"People who are dating have higher levels of sexual satisfaction than (married) couples ... but when they think the relationship is temporary, they're not going to feel as positive about sex," he said.stuff.co.nz