Sex roles and regional cerebral blood flow.

Several investigators have reported higher resting cerebral blood flow (CBF) in females as compared to males. The relationship between sex roles as quantified by Bem's Sex Role Inventory and CBF was evaluated in 106 right-handed, physically and mentally healthy, drug-free volunteers. CBF was measured noninvasively with the 133xenon inhalation technique. The CBF values correlated inversely with age and positively with carbon dioxide levels, confirming previous reports. Females obtained significantly higher CBF values than males; the differences tended to be most obvious in frontal regions. Males and females who scored high on femininity showed higher CBF as compared to low-femininity subjects even after the effect of sex was covaried out. High masculine sex role tended to be associated with lower CBF, but the effect was less clear.