Sex Differences in Olfactory Sensitivity

The reproductive activity of most vertebrates is regulated, at least to some degree, by external stimuli from the ecological and social environments. Classic and well-studied examples include the influences of photoperiod on the seasonal breeding patterns of birds and mammals [1-4] and the effects of conspecific visual and auditory stimulation upon the gonadotropin secretion, ovarian development, and nesting behaviors of certain birds [5,6]. Germane to the field of the chemical senses are the findings that homospecific odors can induce pubertal acceleration, synchronization of estrus, and pregnancy blockage in some mammalian forms [7-12]. In contrast to the effects of external stimuli upon the endocrine system are the less well-studied influences of gender or reproductive state upon sensory function. Unlike the aforementioned work, most of these studies are based upon human subjects. Aside from the wcll-documented sex differences in verbal, spatial, and perceptual motor tasks [13,14], sex differences and menstrual-cycle-related changes in basic measures of human sensory function have been reported for every major sensory system, including vision [15,!6], audition [!7-24], olfaction, taste [25], and the skin senses [26-30]. Although a number of these studies can be faulted on methodologic grounds, the evidence for sex differences and other potentially endocrine-related in-