The current version of the Strong-Campbell Interest Inventory (SCII) contains 37 occupational scales that are "twin" scales, with one scale based on female norms and another based on male norms. The general pattern of scores on these SCII twin scales is for test takers to receive higher scores on the othersex scale than they do on their same-sex scale. However, the various occupational scales differ from one another in their patterns of score differences. Four studies of these SCII twin occupational scales were reviewed, and correlations were developed to show the degree of similarity in the results of those four studies. Those results are summarized on a scale-by-scale basis. Various explanations for the phenomena have been advanced, relating the twin scale score differentials to the masculinity or femininity of the occupations. These explanations were tested with the SCII differential score data with only partial success. This summary of findings from the four SCII studies indicates that counselors will need to know average female and male test-taker scores on other-sex occupational scales to make accurate SCII test interpretations.