A common assumption is that boys are innately superior in analytical and quantitative skills and girls are superior in verbal skills. Research indicates, however, that these assumptions hold true only at certain times in the life cycle of each sex. There is evidence that cultural attitudes, rather than innate sex differences, account for differences in achievement. Males are found to like mathematics if their parents approve of mathematics education, but girls' attitudes are negative under the same condition. The more theoretically oriented teachers (male and female) are, the better are boys' attitudes toward mathematics. Many tests of aptitude or achievement are biased in favor of one sex or the other. This is due to the kinds of questions asked, the manner in which test scores are interpreted or the conditions of test-taking, which sometimes distort results, since boys perform more poorly in stress-producing situations. Attempts of testmakers to obscure differences in performance by boys and girls run counter to the effort of parents and teachers to instill different attitudes and motivations in each sex. Research indicates that only minimal differences in ability and achievement between the sexes can be attributed to physiology. (Author)