Bailey & Pillard - Genetics BLOA

Aim

To investigate the role genetics may play in sexuality

Procedure

Recruited participants through gay publications

Sexual orientations of relatives were noted as well

Used questionnaires to assess childhood gender non-conformity,
- Cross-gender clothing and grooming preferences;
 - Playing with toys generally associated with the opposite sex;
- Preference for playmates of the opposite sex;
- Identification with characters of the opposite sex in stories, cartoons or films.

Participants

Sample was voluntary and all male, monozygotic and dizygotic twins, adoptive brothers

Research Method

Correlational twin study 

Results

52% of MZ twins were both self-identified homosexuals, 22% of DZ twins were so, and 11% of non-related adopted brothers were so.

Participants' self-reported history of childhood gender non-conformity did not predict homosexuality in any of the three samples.

Conclusion

Childhood gender nonconformity does not appear to be correlated with the development of homosexuality. Monozygotic pairs were very similar in their level of childhood gender nonconformity