It has been suggested that the small angle x-ray scattering (SAXS) pattern of human hair can be used to diagnose breast cancer and possibly to identify BRCA1/2 mutation carriers, who are at significantly elevated risk for developing breast cancer. In particular, the presence of a diffuse ring in the SAXS pattern was said to be diagnostic of either breast cancer or an increased risk thereof. To test this hypothesis, we measured SAXS from the pubic hair of 56 subjects with known BRCA1/2 and breast cancer status. We found that there is no clear association between the pattern of SAXS seen in human pubic hair and the risk of breast cancer or the presence of BRCA1/2 mutations. The possible use of SAXS to diagnose cancer remains conjectural, but this and previous studies do not suggest that SAXS can be used as a reliable method of identifying either BRCA1/2 mutation carriers or women who have had breast cancer.