In order to be seen on the podium, the four-foot-seven Ruth Westheimer stands on a stool in front of 200 San Francisco State University students, all sitting spellbound by the sex expert and therapist in their midst.

The moderator reads the students’ pre-submitted questions aloud, and Dr. Ruth, as she’s known, answers the queries with honesty, candour and humour.

“At what age do people stop having sex?” the moderator asks.

“Never!” Dr. Ruth responds. Students burst into laughter and applause.

That declaration was partly why Dr. Ruth visited San Francisco State (SFSU) one afternoon last month.

Officially, she was in town to accept the title of honorary president of the Council on Sexual Literacy and Aging at the San Francisco-based National Sexuality Resource Center (NSRC). The organization also gave Dr. Ruth a lifetime achievement award.

 But she was mainly at SFSU to enlighten.

“Even young people have to hear that it’s all right for older people to be sexually interested and active,” she said the following week in a phone interview from her New York office.

In her on-campus talk, Dr. Ruth spoke about a range of issues, including her efforts to expand research about sexuality and aging.

“Seniors need to know it’s all right to keep their libido, their desire for sex, intact,” she said, adding that her most recent book, Sex After 50, is more of a guidebook than an academic report.

Dr. Ruth said she wants to see another Kinsey study, one that would study heterosexual and gay couples of all ages. In the 1940s, biologist Alfred Kinsey conducted in-depth interviews about sexual history and proclivity with more than 10,000 men and women.

“The Kinsey study is 50 years old. It will be very expensive, but we need a new one,” she said.

A University of Chicago study got the ball rolling in 2007. The study interviewed 3,000 men and women ages 57 to 85 in their homes. The results showed that many men and women remain sexually active, participating in intercourse, oral sex and masturbation,well into their 70s and 80s.

“Americans need to know that older people do have sex as they age,” said Joy O’Donnell, director of strategic partnerships at the NSRC.

“Of course,” Dr. Ruth told the college students, “there are certain limitations. At a certain age, a man cannot hang from the chandelier anymore.” At that, the audience again burst into laughter.

She then explained that older men need physical stimulation to obtain and maintain an erection, and that after menopause, women need to use a lubricant to combat vaginal dryness.

And, she stressed, if seniors are without a partner, “they should masturbate, to keep the libido alive and interested.”

Dr. Ruth also shared her opinion that long-term care facilities, in which residents and patients often share rooms, should have a special room – with a bed, food and beverages – that residents can reserve so that they can have sex in private.

“And a sign should be outside the door that says, ‘Do not disturb,’ like a hotel room,” she said.

An expert on sex from every angle, Dr. Ruth lived in Frankfurt, Germany, until she was 10, and then was sent to a Swiss orphanage for Jewish students escaping the Holocaust. At 16, she moved to Israel and was a member of the Haganah, Israel’s pre-state army.

“I was a sniper in the underground army,” she told the SFSU students. Then, in a jocular tone, she added, “So whoever doesn’t ask me a good question, watch out – I still know what to do with five bullets.”

She came to the United States in 1956 after studying at the Paris-Sorbonne University, and earned a master’s in sociology from the New School of Social Research and a doctorate in education from Columbia University. She became interested in human sexuality after working at Planned Parenthood in New York.

In 1980, she started making radio appearances. Soon, the little lady who looked like your grandmother but used the vocabulary of your best friend became a celebrity and got lots of laughs in the process, with her good-natured, witty take on a topic that was seen as off-limits in the mainstream media.

“My German accent [also] helped me because people knew it was me right when they turned on the radio,” she said.

Dr. Ruth turned 80 in June. She celebrated with 350 friends, relatives and colleagues at the Museum of Jewish Heritage in Manhattan’s Battery Park.

“There was a lot of dancing. I danced the whole evening,” she said. “And I was very lucky – there were even fireworks. I didn’t order them. No, they just happened to go off.”

 In her talk at SFSU, it was clear that Dr. Ruth’s enthusiasm, energy and knowledge are still wholly intact, and she shows no signs of slowing down anytime soon.

 “I even managed to see Muir Woods,” she said of her trip to California. “My only regret was that I did not get to see the [Contemporary] Jewish Museum and the exhibit of [Andy] Warhol’s Jews. Next time.”