A study conducted by researchers at the University of Texas and published in BMC Women's Health has found that most women find a wide penis more satisfying than a long penis. The study, led by psychologist Russell Eisenman, was conducted by interviewing female undergraduate students and asking them about the effect of penis width versus length on female sexual satisfaction. The survey found that 90 percent of the women interviewed reported that width felt better, while 10 percent said length felt better. None of the study subjects said they could not tell any difference.
It was not obvious why a wide penis would be preferred to a long penis, said Eisenman. "Penis width may be important due to a penis thick at the base providing greater clitoral stimulation as the male thrusts into the female during sexual intercourse. That is, a wide penis would seem to offer a greater degree of contact with the outer part of the vagina, including the clitoral area. If this is correct, then Masters and Johnson are wrong about penis size being unrelated, physiologically, to female sexual satisfaction.
Masters and Johnson have said that penis size should have no physiological effect on female sexual enjoyment, since the vagina adapts to fit the size of the penis. The current results call this conclusion into question, and point to the importance of penis width."
The researchers concluded that penis width needs to be given more consideration, and taken into account when discussing penis size. Also, it may be that Masters and Johnson were wrong about penis size having little or no physiological effect on women's sexual satisfaction. However, the current data cannot provide a final answer, since they are based on self reports of women surveyed about penis length versus width, and their sexual satisfaction. With the survey method used, the results reflect either a psychological preference or a true physiological reality, but the researchers cannot say which.