The use of health-related physical fitness tests for sex-fair ability grouping in physical education classes requires the verification of two assumptions: (1) that there exists a direct positive relationship between health-related physical fitness and development and/or improvement of various sport skills; and (2) that there is a physiological capability of both sexes to perform equally on health-related physical fitness test items. Health-related physical fitness tests involve cardiovascular function (1-mile run), body composition (triceps and subscapular skinfolds), and musculoskeletal function of the abdominal and low back region (timed sit-ups and sit and reach exercises). A comparison of selected percentile norms from the AAHPERD (American Alliance for Health, Physical Education, Recreation and Dance) Health Related Physical Fitness Test Manual shows that, with the exception of the flexibility item, if percentile scores are used for classification, true homogeneous groups based on absolute fitness will not be achieved. The use of absolute scores to achieve sex-fair groups would require the establishment of criterion-referenced norms for the individual groups and probably result in an unequal sex, but equal fitness, distribution of students. (Author/JD)