Advances in medical science have extended not only human life spans, but virility during the course of those longer lives.

That fact has been accompanied by a growing body of research into the sexuality of people who have passed what is to be considered retirement age. Now, a new Australian study shows that both sexual activity and a desire for sex remain a consideration for men who are approaching the century mark.

"Although many people, including some doctors, believe that sexuality isn't important to older people, our study shows that this is not the case. Even in the tenth decade of life, 1 in 5 men still considered sex important," said study researcher Zoe Hyde, a doctoral researcher with the Western Australian Centre for Health and Ageing at the University of Western Australia. "However, some common medical problems are barriers to older people remaining sexually active," Hyde said.

The Australian study comes after studies in the United States and Sweden have shown that many or most people in their 70s lead active sex lives, and have found high levels of sexual satisfaction among this group, sometimes even exceeding that of their younger years.

The new study looked at nearly 2,800 men between the ages of 75 and 95. While sexual activity and the desire for sex was lower than in studies of younger adults, it remained significant. Nearly a third of the men surveyed had had sex in the past year, and just under half considered sex to be "at least somewhat important."

Of those who were still sexually active, more than forty percent wished to have more, but were blocked, often by their own health problems or their partners' problems, including conditions such as osteoporosis, diabetes, prostate cancer or other physical limitations.

Men who wish to be sexually active late in life can take some preventative steps in their younger years, Hyde said.

"Chronic disease, such as diabetes, appears to be the main reason that older men cease being sexually active," she told MyHealthNewsDaily. "If men want to remain sexually active as they age, the best thing they can do is get sufficient physical activity, eat a healthy and nutritious diet and stop smoking."

Hyde said the study has also highlighted other things that may help people who are older stay sexually active if they wish.

"It was interesting that testosterone levels were still associated with sexual activity, after we controlled for medical problems and social factors," she said. "This suggests that testosterone deficiency could possibly cause problems for some men, so this is an area that clinical trials of testosterone therapy should look at."

Testosterone therapy has been advocated to stop age-related decline in men, but it remains controversial because of a lack of data on its risks and benefits.

"It would be premature to suggest testosterone therapy to improve sexual interest and activity at this stage," Hyde said. "We need further studies to properly explore the risks of therapy as well as the possible benefits."

The study did hold some caveats. The authors noted that the men in the study lived in the community, and may not represent the population of men in that age range as a whole, some of whom live in assisted-living facilities.

But researchers also noted that some men might have been reluctant to be more honest in their responses because "sexuality can be a sensitive topic."

Judith Kuriansky, a clinical psychologist and adjunct faculty member of Columbia University Medical Center’s Department of Psychiatry, said the new study is not surprising in light of research from other countries.

"Men who are over 75 are not over the hill anymore," Kuriansky said.

Because there are more women than men who live to that age, "They, I'm sure, have lots of partners to choose from," she said, adding that "with all these medications that are available, they can still perform longer."

Kuriansky said one of the impacts she hoped to see from the research would be a rethinking of how people might spend their later years. She said the presence of a greater number of more virile men "has implications for medical plans and social issues and government policy."

For example, mandatory retirement ages, she said, present one problem, because not only are men active for longer, they would also demand more benefits in Social Security and retirement benefits to maintain an active lifestyle.

"It's changing the definition of what old is, so the cutoff should be higher," Kuriansky said.

Pass it on: Men in their 70s, 80s and 90s are sexually active, and almost half wish they were having more sex.

This article was provided by MyHealthNewsDaily, a sister site to LiveScience.