From the Research
Sexual orientation is likely influenced by both genetics and environmental factors, with neither being solely responsible, as suggested by the most recent and highest quality study 1. Current scientific evidence suggests it results from a complex interplay of biological, genetic, hormonal, and environmental influences during development. Genetics appear to play a role, as studies of twins and families show some heritability of sexual orientation, with a study finding linkage support at pericentromeric chromosome 8 and chromosome Xq28 1. However, there is no single "gay gene" - rather, multiple genes likely contribute small effects. Environmental factors in the womb, such as prenatal hormone exposure, may also shape orientation, as suggested by a study on women with congenital adrenal hyperplasia (CAH) who have higher rates of nonheterosexual orientation compared to non-CAH women 2. Post-birth factors like family dynamics, culture, and personal experiences can further influence how orientation develops and is expressed. But there's no evidence that parenting or childhood experiences alone determine orientation. Importantly, sexual orientation is not a choice and cannot be changed through therapy or other interventions, as it is a natural variation in human sexuality that typically emerges in adolescence as a core part of identity. Some key points to consider include:
- The complexity of sexual orientation and the need for further research to fully elucidate the biological and environmental pathways involved 3, 1, 4, 5, 2
- The importance of considering both genetic and environmental factors in the development of sexual orientation 1, 2
- The lack of evidence for a single "gay gene" and the likelihood that multiple genes contribute small effects 1
- The potential role of epigenetic mechanisms in shaping sexual orientation, particularly in cases where individuals are exposed to high levels of hormones in utero 2