Many studies in nonhuman species have shown that gonadal steroid hormones can influence the regional structure and physiology of the central nervous system, and can bring about both short- and long-term effects on behavior. The extent to which human behavior and thought processes are subtly influenced by the hormonal milieu is unclear. There is preliminary evidence from a number of clinical endocrine syndromes, and from studies of normal human subjects, that sex steroids may modulate the expression of certain specific cognitive abilities. This paper will briefly review some recent evidence suggesting that visual-spatial abilities are among the cognitive functions that may be affected.