Sexuality researcher Beverly Whipple made her name a quarter century ago popularizing the "G spot," the elusive female erogenous zone, but she has a different message these days: Move on.

"There's so many ways that women can have sexual pleasure," Whipple said. "We can't deny the experiences of women. We have to validate them."

Lesson number one: The biggest sexual organ really is the brain.

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The longtime Rutgers University nursing school professor officially retired about five years ago, but still keeps a hectic schedule, doing research, writing, giving interviews and jetting off to speak at sexuality and women's health conferences around the globe.

Her most recent book, "The Science of Orgasm," co-written with Rutgers neuroscientist Barry Komisaruk and Mexican endocrinologist Carlos Beyer-Flores, explores how the brain produces orgasms and the complex biological processes involved.

It documents groundbreaking work showing that, contrary to what doctors tell them, some women with spinal cord injuries can still climax.

Whipple said women with such injuries who were still experiencing orgasm came to her for support, so she began a study of others with the same injury.

"One woman had six orgasms in 24 minutes," after none in the two years since her injury, Whipple recalled. "She was crying. I was crying."

Amusingly packaged in a plain brown wrapper, the book also reports that women can climax after stimulation to a number of body areas or from mental imagery alone.

It also covers the health benefits of sex and how aging, medications, diseases and hormone changes affect orgasm in both men and women.

Published in October, it's selling well enough that a second printing is in the works.

Internationally renowned, Whipple, 65, serves as a consultant on sexuality issues to the World Health Organization and other agencies, and has had her works cited in outlets as incongruous as Modern Maturity and Playboy.

Last fall, she was named one of the world's 50 most influential living scientists by New Scientist magazine, the latest of many awards for her decades of research on sexuality and sexual health.

A grandmother of five, Whipple is so soft-spoken it's almost jarring to hear her talk in graphic, but clinical, sexual terms.

Whipple, who has been married for 44 years to husband Jim, a retired rocket scientist, seems single-minded in her goal of helping couples improve relationships and better enjoy sex.

"I would hope women are saying what they find pleasurable and satisfying" with their partner, she said in an interview in her airy, neat-as-a-pin home in Voorhees, a suburb southeast of Philadelphia. "I've devoted my whole career to this."

In the mid-1980s, Rutgers asked her to join the faculty. She told them she wouldn't come aboard unless she could conduct research on women, who had been neglected in medical research. The university's nursing school then offered her a laboratory to seal the deal.

Whipple has particularly tried to help women who feel confused or weird because their own bedroom experiences don't match conventional wisdom or Hollywood portrayals of sex.

"Women just thanked and thanked and thanked us for helping them feel normal," Whipple said. Her first book was so well received, she took a 1½-year leave for a U.S. and European book tour.

The new book discusses how orgasms or pressure on a woman's G spot can reduce pain, a discovery that may lead to a new painkilling drug and training people to limit pain with their brain.

"She's really on that forefront of trying to understand the relationship between how we perceive things in our brain ... and how they're related to anatomy and chemistry," said Stephanie Sanders, an associate director of The Kinsey Institute for Research in Sex, Gender, and Reproduction at Indiana University. "I think that's where her work is so exciting."

While some scientists still dispute whether the G spot exists, Whipple says she and her colleagues have found one in every woman they've examined and other scientists duplicated their results, including through autopsies of women.

The G spot is a sensitive area that can be felt through the front wall of the vagina between the back of the pubic bone and the cervix. It feels like a small lump, swells when stimulated with heavy pressure and can trigger intense orgasm. Because it's tough to find, it's remained controversial.

Dr. Brunhild Kring, a psychiatrist at New York University specializing in sexuality issues, said she thinks only some women have a G spot and that only some couples — sort of "sexual athletes" — are able to enjoy it.

Kring said Whipple's recent work is more sophisticated with its focus on issues including the complex role of nerves and brain chemicals as they relate to sexual pleasure.

"What she's really contributed is that there are different ways to reach orgasm and that one's not more valuable than another," Kring said.

Whipple, a trained nurse, worked as a nursing school instructor early in her career, but switched to sexuality research and education after a student asked her: "What can a man do sexually after having a heart attack?"

Whipple realized that even then — in 1975 — nursing schools didn't cover sexuality. That nudged the Secaucus, N.J., native into her niche.

Unlike other researchers who had gleaned information on Americans' sex habits and preferences from face-to-face interviews or large, anonymous surveys, Whipple and her collaborators worked in a laboratory, doing studies on female volunteers to learn how sexual organs, nerves and the brain interact.

Early on, she and a former collaborator, psychologist John D. Perry, discovered their volunteers had a mysterious, sensual area inside.

Researching medical literature, they found Dr. Ernst Grafenberg of Germany had reported in 1950 that women have an erotic zone there that causes orgasm.

They named it the Grafenberg spot, or G spot, and created a stir when they reported on it at a medical conference and in their 1982 book, "The G Spot and Other Discoveries about Human Sexuality." The international best-seller, printed in 19 languages, was updated and reissued in 2005.

Some feminists and researchers weren't thrilled with the book.

Shere Hite, author of the groundbreaking 1976 book, "The Hite Report on Female Sexuality," said Whipple's focus on the G spot slowed the drive for women's sexual equality, coming after both Hite and the Masters and Johnson research team documented that more women climaxed from clitoral stimulation than intercourse.

The G spot book suggested intercourse alone should satisfy women, said Hite, who continues to research sexuality and write books and columns on the topic.

On the other hand, Judy Norsigian, executive director of Our Bodies Ourselves, the education group that publishes the women's health bible of the same name, called Whipple's book an important advance.

"It really furthered the science of women's sexuality and of orgasm quite a bit," she said.

Asked how all her research has affected her sex life, Whipple, a petite woman who remains trim with frequent exercise, avoided a direct answer.

"Our bedroom is not my research laboratory," she chuckled.