The long-running battle of the sexes over who feels the most pain has been won.
Sophisticated brain scans show that women have more intense responses to pain than men.
The reaction from the stronger sex is concentrated in parts of the brain involved in pain avoidance, according to new research.
A study using MRI brain scanners found women process pain in the brain differently to men.
Doctors were investigating gender differences in how the sexes respond to the pain of chronic conditions such as Irritable Bowel Syndrome - which affects more women than men.
But the findings also shed light on the age-old debate about the sensitivity of the sexes.
The perception of pain is influenced by a number of factors, according to Dr. Roger B. Fillingim of the University of Florida, Gainesville.
"Pain is not what travels along the nerves,"' he said. "Pain is our own personal experience."
He noted that women are two to three times more likely to have migraine headaches than men are, and women are six times more likely to have fibromyalgia--a syndrome characterized by chronic pain in the muscles.
Another research team from London and Japan led by Professor Qasim Aziz, of the Wingate Institute for Neurogastroenterology, Queen Mary University of London, studied brain activity and reactions of 16 men and 16 women in the anticipation and processing of pain.
The study involved healthy volunteers who were told that a tiny balloon would be expanded in the gullet, before the procedure lasting a second.
During the period leading up to it, women had less activity in areas that process fear and more activity in areas involved in preparing and planning movements to avoid the impending pain.
In men, fear was predominant when they were expecting to feel pain.
During the painful event the opposite reaction was seen among men who were more involved with pain avoidance.
In contrast, women showed greater activity in areas involved in processing emotions and feeling the pain.
Findings from the scans will be released today at the British Society of Gastroenterology's annual meeting in Birmingham.
Prof Aziz said 'The fact that during pain our female subjects showed more activation of the emotion processing areas in the brain could suggest a mechanism whereby females may attribute more emotional importance to painful stimuli which may influence how they perceive, report and respond to pain in comparison to males.
Research by Jeffrey S. Mogil, professor of psychology at McGill University in Montreal, Canada, suggests that men and women use separate mechanisms in the brain to achieve pain relief.
By studying genetically modified mice, Mogil and colleagues have discovered that kappa-opioids, the same pain relievers UCSF researchers found were more effective in women, work through different pathways in female and male mice.
'Further research is now required to assess the clinical importance of these findings and to determine if brain imaging studies can help to guide therapy.'
About one in five people suffer gastrointestinal disorders such as dyspepsia and IBS, which affects three times as many women as men.
Symptoms such as pain, flatulence, bloating and constipation or diarrhoea are chronic.
Antidepressant and painkilling drugs are often used but often poorly control the symptoms.
Professor Jon Rhodes, president of the British Society of Gastroenterology said 'This is a fascinating study that uses the latest non-invasive technology to assess how the brain works.
'It gives new insight into the mechanisms that underlie functional abdominal pain due to conditions such as irritable bowel that cause great nuisance and distress to so many people.
'There is a good chance that it will lead to development of new treatment strategies.'