Sex, gender, and pain: women and men really are different.

Sex-related differences in the experience of both clinical and experimentally induced pain have been widely reported. Specifically, females are at greater risk for developing several chronic pain disorders, and women exhibit greater sensitivity to noxious stimuli in the laboratory compared with men. Several mechanisms have been proposed to account for these sex differences. Psychosocial factors such as sex role beliefs, pain coping strategies, mood, and pain-related expectancies may underlie these effects. In addition, there is evidence that familial factors can alter pain responses, and these intergenerational influences may differ as a function of sex. Sex hormones are also known to affect pain responses, which may mediate the sex differences. Although the magnitude of these effects has not been well characterized, there are potentially important practical implications of sex differences in pain responses. These implications are discussed, and directions for future research are delineated.