Homosexuality; Nature vs. Nurture

10 Mar

Whilst the American Psychological Association (APA) have changed their original classification of homosexuality from being a mental illness in 1975, it was only in 1994 that the APA put out a statement saying “…homosexuality is neither a mental illness nor a moral depravity. It is the way a portion of the population expresses human love and sexuality” (American Psychological Association, 2010). Today they claim that being homosexual is not a choice and that “…it emerges from most people in early adolescence with no prior sexual experience” (APA, 2010). There are many arguments about whether homosexuality is a consequence of a person’s upbringing, or genetics.

In 1990, Swaab & Hofman discovered that the hypothalamus in homosexual males brains differed to that in a heterosexual’s brain. Other studies have also found this to be true, suggesting that homosexuality is genetic. Twin studies by Bailey and Pillard (1991), discovered that if one identical twin was homosexual, there was a 52% chance of the other one being so too, the chance was lowered to 22% for non- identical twins and only 11% for non- related adopted brothers. This research also suggests that homosexuality is genetic, supporting the nature side of the debate. Then in 1993, Hamer discovered the ‘gay gene’; the X-Chromosome called Xq28. This Chromosome was found to have certain markers in 64% of both homosexual brothers.

Despite sufficient evidence for the nature side of the debate, sociobehaviourists do not agree, claiming that homosexuality is caused by environmental factors, especially in childhood. In 1999, Wickelgren questioned Hamer’s study and concluded that the link is too weak between the Xq28 Chromosome and homosexuality. Parenting has been suggested to cause some people to be homosexual. Factors such as whether boys were allowed to play with dolls, or treated like a ‘sissy’ girl, have been linked to homosexuality, as well as child abuse (Nicolosi, 2002). If someone was to take the view of a Tabula Rasa, a blank slate, then it could be argued that upbringing must be the cause of homosexuality.

[Graph above retrieved from: Satinova, J. (1995). The Complex Interaction Of Genes And Environment: A Model For Homosexuality. Collected Papers from the NARTH Annual Conference.]

The above graph shows some possible environmental effects which could contribute to homosexuality and the percentage of relevant genes inherited. It suggests that both nature and nurture contribute, but neither are essential.

The nature side of thedebate has much more scientific and reliable research conducted in favor of it. Many ‘nurture’ factors could contribute to homosexuality developing, but it is likely that the persons susceptibility to be homosexual is due to genetics and ‘nature’. Whilst genetics may not always be the cause, there is no doubt that the nature side of the debate is a valid theory.



Bailey, J. M., & Pillard, R. C. (1991). Genetic Study of Male Sexual Orientation. Arch Gen Psychiatry, 48(12), 1089-1096.

Hamer, D. H., Hu, S., Magnuson, V. L., Hu, N., & Pattatucci, A. M. (1993). A linkage between DNA markers on the X chromosome and male sexual orientation. Science, 261(5119), 321- 327. DOI: 10.1126/science.8332896

Nicolosi, J., & Nicolosi, L. A. (2002). A Parent’s Guide to Preventing Homosexuality. Intervarsity Press.

Publication Manual of the American Psychological Association, 6th ed (2010). Washington, DC: American Psychological Association.

Swaab, D. F., & Hofman, M. A. (1990). An enlarged suprachiasmatic nucleus in homosexual men. Brain Research, 537 (1-2), 141- 14. http://dx.doi.org/10.1016/0006-8993(90)90350-K

Wickelgren, I. (1999). Discovery of ‘Gay Gene’ Questioned. Science, 248(5414), 571. DOI: 10.1126/science.284.5414.571


3 Responses to “Homosexuality; Nature vs. Nurture”

  1. psuf1d March 13, 2012 at 9:59 pm #

    A number of studies, focusing solely on homosexuality among women present the idea that women develop same sex attraction due to a number of different factors in early development.

    The first is failures of attachment with the mother which in turn leads to the child rejecting the mother as a role model. This disruption in attachment with the parent interrupts the process of gender identification and in turn they develop an unconscious search for mothering (Moberly, E,1983).

    The second factor is the relationship with the father, many homosexual women have reported a very close relationship with the father and it suggested that due to this, the child disowns her femininity (Bell, A., Weinberg, M. & Hammersmith, S. 1981)

    Finally, temperament also seems to influence the development of same sex attraction in women. Homosexual women have been found to generally be of high intelligence, creative, possess a strong sense of curiosity and capacity to feel, they also have a strong sense of justice and are usually quite active.(Hallman, J. 2004).

    This clearly demonstrates that nurture has a significant influence on the development of same sex attraction among women.


    Bell, A., Weinberg, M. & Hammersmith, S. (1981). Sexual
    preference: Its development in men and women. Blomington, IN:
    Indiana University Press.

    Moberly, E. (1983b). Psychogenesis. The early development of
    gender identity. London: Routledge & Kegan Paul Limite

    Hallman, J. (2004). Techniques used in treating women with SSA.
    Collected Papers from the NARTH Annual Conference, NARTH,
    Encino, CA.

  2. riggerb March 14, 2012 at 1:56 pm #

    i found this blog really interesting and something that i have had many discussions on in the past. There does seem to be alot of evidence to suggest that homosexuality is nature.
    I found this very interesting paper written by the guardian http://www.guardian.co.uk/science/blog/2009/jun/17/same-sex-relationships-gay-animals.
    It says that alot of animals go through life homosexual. That they either have one mate who is of that same sex or they have a partner but also mate with same sex partners. Or in the odd case of the marine snail they both start out as males and then one of them becomes a female. Although we are far from related to some of these animals to see that animals have same sex relationships suggest that it is nature and it is something that has happened throughout evolution and different species for decades.

  3. anastasiaelizarova March 14, 2012 at 2:00 pm #

    An issue with little levity, the sexuality pertinent to an individual has preconceived (within either personal, anecdotal instances or in regional and global legal cases), inadvertently, their quality of life; the manner in which society brings forth their treatment, unfortunately negatively inclined if one obtains same-sex tendencies. In regards to the brain structure, it may have been preferred for further clarification as to what extent structures, and what kind (neuronal, mass) mould sexual identity and if further irregularities (i.e. schizophrenia) may ensue. Regarding the types of twins and subsequent concordance rates, is it not a prodding curiosity to know why not all twins share the gene unconditionally – if one is one sexuality, why is it not identically shared? What prohibits such ‘consistency’? Yet, it is evident intervening variables are inevitable, thus demonstrating the aforementioned rates – as shown by a study conducted by Bailey and Pillard (1995). Among the 153 million base pairs (1168 genes) of X chromosomes, and the 50 million (251 genes) of Y chromosomes, further research is deemed to unravel a mediating factor of ‘compromise’. One of momentary concern, in relation to the blog entry, is the proclaimed ‘bi-sexual gene’. To logically draft, one must consider: One’s natal day, in addition to bestowing the earth with life, produces a being as a compilation of the biological parent’s genes. The gene determinant of one’s sexuality is ideally neutral, initially. Like a muscle, if not worked out or engaged, the gene will gradually atrophy if subject to certain conditions by the environment, and conversely fortified with others. The conditions, however, are of primary concern and question – what conditions determine, simply, what? In nature vs nurture, one cannot simply abolish the other. An enticing entry, a field from which further research simply must branch, permitting societies to no longer perpetuate hatred due to misunderstanding, or reluctance due to unfounded conceptions of one’s biological genes. Thank you.



    Bailey JM, Pillard RC (1995). “Genetics of human sexual orientation”. Annual Review of Sex Research 6

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