Number of X-linked androgen receptor gene CAG repeats and femininity in women

Two studies used a sample of 300 female Australian monozygotic twins who had been genotyped for the X-linked androgen receptor gene and scored for the number of repeats of the triplet CAG. (A low number of repeats is associated with greater risk of prostate cancer in males and more effective transcription of androgens). In the first study, three measures of masculinity–femininity were constructed from the items of two personality questionnaires that had been taken by the members of a large twin sample ( 3000 pairs). Two of the three measures, admitting to fears and worries and a willingness to break rules, were not significantly correlated with number of CAG repeats in the genotyped subsample. The third measure, confiding in others versus reserved, showed a small but significant correlation with CAG repeats in this female sample: fewer repeats went with scores in the reserved (i.e. masculine) direction. In the second study, CAG repeat scores were correlated with 90 questionnaire items related to female reproductive functions. Three items were associated with fewer repeats: age, having had a hysterectomy and length of labor at the birth of a second child. Because many items were screened, this was regarded as suggestive but not conclusive evidence of an association of CAG repeats with these reproduction-related traits.