Physiological predisposition toward becoming a cigarette smoker: experimental evidence for a sex difference.

In two experiments, nonsmoking females whose urine was acidified were more willing after smoking one cigarette to volunteer to smoke additional cigarettes than were females whose urine was made alkaline. Males did not exhibit this effect. The results indicate that physiological factors that influence nicotine intake during the early smoking experiences of nonsmokers help determine who becomes a cigarette smoker, at least for females. These results may help us interpret recent increases in smoking among teenage females.