Both groups of factors – genetic and environmental – impact people’s choice of sexual orientation. There is a lot of evidence of both the genetic mechanisms’ and surroundings’ influence on people’s sexual preferences. However, between the two, the environment more responsible for such a choice.
While some researchers consider genetic mechanisms to be the most decisive element in the formation of sexual orientation, other scientists prove that the environment plays an important role here. For instance, the study performed by the Academy of Science in South Africa shows that there is a strong connection between homosexuality and the environment (Pepper & Kramer, 2015).
Research indicates that homosexual men usually have a larger number of older brothers than heterosexual males. Also, there is a greater possibility for homosexual and transgender men to have homosexual brothers than for heterosexual males having homosexual siblings (Pepper & Kramer, 2015). The same thing concerns women: homosexuality is more likely in families with many sisters or in females who have homosexual sisters.
Another group of factors causing homosexuality and transgender disorders is associated with external environmental issues (Pepper & Kramer, 2015). Exposure to pesticides, dangerous chemicals, substances, and toxic compounds may lead to the appearance of epigenetic marks that are believed to cause changes in the future mother’s hormonal system. Such an impact may result in changes in sex hormones levels (Pepper & Kramer, 2015).
Therefore, due to the results of the studies, environmental factors have a greater impact on sexual orientation than genetic ones. Still, more research is needed to answer this question in the most comprehensive way.
Reference
Pepper, M. S., & Kramer, B. (2015, June 11). Here’s what we know about the science of sexual orientation. Slate.