The Web is having a conversation about senior sex, and it's a mixed bag of disgust, defensiveness, zealotry, and hope.

For the young, sex over 60 is comedy tinged with embarrassment. They view with alarm parents' and grandparents' forays into the erotic, and speak of it in cartoon terms.

For senior sex activists, sex over 60 is cause for slash and burn advocacy that must leave no impediment to the doggone truth that senior sex is hot, hot, hot.

For merchandisers, pitching sex toys to seniors has paid off handsomely, and there is a growing enthusiasm for senior porn (the wildly popular Japanese porn star Shigeo Tokuda is 76).

For seniors themselves, it's a tug-of-war between can-do and eee--eww. Passion remains undiminished for healthy men and women, but it can be tempered by poor body image, strength and flexibility issues, absent partners, and the way our culture has framed sex as athletic performance.

We need to consolidate the senior sex discussion in a hurry. Dr. Aubrey De Grey, a biomedical gerontologist, has famously said that the person who will live to be 150 has already been born. I hope this means that soon no one will dare to think that a 60th birthday is a cutoff date for sexual endeavor. Who wants to live their last 90 years without sex?

The idea persists that vibrant, energetic sex is only for the young -- what could be left for us older folks but fond memories and chaste hugs? Most egregious of the end-of-sex myths is the belief that erectile dysfunction routinely descends upon men in late middle age. Whether or not this myth is encouraged by companies eager to sell drugs and devices, and by stand-up comics with an excess of ED jokes, the fact is that too many 50-plus men believe it, and too many waste time and libido waiting sullenly for the day when the equipment fizzles and dies, like a fuse in a dimmer switch.

In the days when I traveled long miles with a three-man documentary film crew, we filled the time with chatter about whatever came to mind. One winter afternoon, as we drove into the sunset, the cameraman let us know he'd soon mark his fiftieth birthday. "At this age a man loses his sexual powers," he said gloomily, without a trace of irony.

I waited for manly and dismissive guffaws from the other two men, who were also in their mid-to-late forties. Instead there were grim nods and grunts of acceptance. I was stunned at the moment and later quite sad. With their brains working against them (the brain being the body's largest sex organ) all three of these seemingly vigorous guys were in for some profoundly unnecessary disappointment.

Dr. Mehmet Oz, who calls the penis "the beautiful dipstick of health," and Dr. Michael Roizen, author of The RealAge Makeover, are working to overcome age-bound impotence theories. They are among many in the medical and scientific communities who proclaim that sex is central to well-being at any age. They support studies that show a relationship between satisfying sex and longevity. "The more sex a person has, the less aging he or she will undergo," Dr. Roizen promises.

Both doctors are cautious about forming simple truths from the still-small body of sex-longevity research, but they are convinced that high quality orgasms -- and plenty of them -- help us live longer. People who engage in robust sexual activity seem less likely to succumb to age-related diseases, they say.