A Genome-Wide Study of Male Sexual Orientation Bolsters Prenatal Thyroid Theory

The authors (Alan Sanders et al., 2017) of a genome-wide association study have reported that male homosexual orientation is associated with two regions located on chromosomes 13 and 14. On chromosome 14, the thyroid stimulating hormone receptor (TSHR) gene was found to span the most significant region that confirms past findings relating familial atypical thyroid function and male homosexuality. In Graves's disease, TSHR codes for the major autoantigen in the autoimmune hyperthyroidism. The paper cites Sabuncuoglu's work as follows: "...…Furthermore, a recent retrospective chart review of 790 adolescents (8 to 17 years) previously admitted to a child psychiatry service found 15 mothers with a history of thyroid dysfunction during pregnancy, 16 adolescents with a history of same-sex attraction and/or gender nonconformity, and 12 overlapping mother-offspring pairs with both (p < 0.0001), suggestive of a possible relationship…" Headlined in several internet and mass media, the findings of the study was a great surprise for those who are still unaware of Prenatal Thyroid Theory. Even in an unlikely design to confirm the Prenatal Thyroid Theory, the positive findings are in no way surprising as Sabuncuoglu had noted in his 2015 paper that: "...…The genetic model is also under scrutiny. It is not surprising to find significant results for homosexuality in genetic studies as prevalent thyroid disorders (i.e., Hashimoto thyroiditis) have a very strong genetic background. In the search for possible factors for the persistence of homosexuality in human populations, thyroid disorders provide a reasonable explanation as they are prevalent and more common in women." We do not think that Graves's disease is the main path to contribute to male homosexuality. First of all, even Graves's disease is much more common in females. Yet we can eagerly claim that a genetic study on female homosexuals will reveal stronger positive results for Hashimoto's thyroiditis. As we note here :)