After her divorce at the age of 45, Linda assumed her sex life was over.
That was OK, the Ann Arbor, Mich., social worker told herself. She was nearing menopause and not too far away from earning the moniker "senior citizen." She figured it was natural -- inevitable, even -- that such desires grow tired and fragile with time, like bones.
They didn't. One year without physical intimacy became two; two became three and then four. Her longing never ceased.
"It surprised me -- how important it seemed," Linda says. "I missed it so much."
Finally, she met a man for whom she felt enough affection to become sexually involved. Over the next decade, she met a few more like him. With each, the desire she felt and the pleasure she took were undiminished by her accumulating years.
Now 60, Linda, who asked that her real name not be used, is involved in a long-term, monogamous relationship with a man of the same age.
They have sex at least twice a week -- as often as she had it in her late 30s and early 40s. It's different: Menopause triggered vaginal dryness, so she uses store-bought lubricants. But it's just as good, she says.
"I know a lot of women my age and older who don't have sex anymore and say it doesn't matter," Linda says. "I think it does. I think people give up too easily because they assume that's how it should be."
They're wrong. While various aspects of sex change as men and women grow older, the idea that it stops being desirable, pleasurable or even possible is a fiction spun by a prudish culture that assumes carnal pleasure to be the exclusive province of the young, most experts say.
"Nothing could be further from the truth," says Dr. William Masters, the trailblazing sexual researcher. "There may be less frequency, but the interest is still there. So is the ability."
Some of the lost frequency, in fact, has more to do with the intimidation older people feel in the face of subtle and overt cultural messages that they should no longer be sexual. Some of it has to do with ignorance regarding the changes happening to their bodies.
Just how often people in their 50s, 60s and 70s have sex isn't really known, experts say; scientists still have a poor handle on human sexuality in general.
Surveys into sexual behavior are notoriously inaccurate, compromised by interview subjects' evasions and half-truths.
A 1989 poll by the Guttmacher Institute of more than 1,300 people found that the number of times a year they reported having intercourse peaked in the 30-39 age group and then dropped steadily in each older age group.
The most precipitous decline came between the 60s and 70s. Those in their 60s reported an average of 22.6 occasions of sexual intercourse in the past year. Those in their 70s reported an average of 8.2.
For a man, aging reduces the readiness and stamina of his erection. Impotence rates dramatically increase.
For a woman, sexual aging is less dramatic. It does not occur on the same steady curve but mainly in a specific passage: menopause, which generally occurs in the 50s. After menopause, a woman may notice that she has less natural lubrication in her vagina. In fewer cases, she may notice some actual shrinking of the vaginal cavity, though usually not until the 70s.
If older men and women are basically healthy, comfortable with their bodies and flexible in their notion of what shape a sexual encounter can take, there's no reason they shouldn't have good sex lives into their 80s, experts say.