Monica Jarrett, PhD, a researcher and associate professor of biobehavioral nursing and health systems at the University of Washington in Seattle, says the new study makes sense. She notes that many pain studies make use of self-reports and that, in dealing with the nerve fibers, Dr. Wilhelmi's research involved more objective measurements.

But both scientists point out that nerve fibers alone don't explain differences in pain perception. It's much more complicated than that. Among a host of other factors, says Dr. Wilhelmi, are cultural influences, "the environment one is brought up in." Life experience plays a role too, he says: "If someone has been through a lot of intense athletics or military training, they may have trained themselves to experience pain to a lesser degree."

Perceptions of pain can also be influenced by how stressful a person's job is at the moment and how well they are getting along in their social environment, adds Jarrett.

But physical differences, like the differences in nerve fibers found by Dr. Wilhelmi, could definitely play a role in pain perception, says Jarrett. She studied women with irritable bowel syndrome (IBS), comparing them to women without. "What we see is women with IBS clearly take more over-the-counter medicines for pain than do women who don't have IBS," she says. She thinks the bowels of those with IBS may have increased visceral sensitivity and that, therefore, those people feel the pain more acutely. "Your bowel may start off more sensitive or develop a sensitivity from infections or other problems," she explains.

For women, the research suggests it's wise to keep an eye on how well pain medications work and report to their doctor if the medicines don't seem to be doing the job, says Dr. Wilhelmi.

Some other studies have also found women feel pain more than men, but there are exceptions. For example, two recent studies at the University of Missouri, published in the Journal of the American Pain Society in 2008, examined how college men and women experience muscle pain and let it affect them.

The only difference found was that women were less active than men on the third day after exercise-induced pain. There were no sex differences in ratings of pain and no other differences in impact of pain on activities. Perhaps that study suggests that women are becoming more likely to deal with pain like men have long been socialized to: by walking it off.

Sources: Bradon J. Wilhelmi, MD, plastic surgeon, Southern Illinois University School of Medicine, Springfield; Monica Jarrett, PhD, associate professor of biobehavioral nursing and health systems, University of Washington, Seattle; Plastic and Reconstructive Surgery, October 2005; Journal of the American Pain Society, March 2008