Many academic examinations exhibit sex differences in terms of entry figures and pass rates. This fact is illustrated by a selection of statistics from the British GCE "O" level examination results for June 1976. These results are discussed in terms of three possible causes: innate differences in intellectual functioning, sex role stereotyping, and sex bias in the examinations themselves. The research evidence concerning sex differences in intellectual functioning seems inconclusive, and certainly does not seem to indicate any large and consistent differences. Where differences do exist it is also impossible to assume that they are innate, as the influence of socially defined sex role stereotyping is apparent. The link between sex role stereotyping and sex differences in attitudes to various academic subjects also seems to be a distinct possibility. In addition to this, the evidence for the effect of attitude on performance makes the sex role stereotyping explanation for these results a most realistic one. The possibility of sex bias in the examinations themselves was not completely ruled out but, like the innate differences hypothesis, this did not seem to be a tenable explanation for the overall size of the differences. (Author)