N.E.Whitehead, Ph.D, 2008
Dean Hamer (whose name is particularly associated with “gay gene” studies) has an interview segment on YouTube from an ex-ex-gay website in which he says that upbringing has nothing at all to do with the development of homosexuality. The reason he says that goes back basically to studies from 1981. But a recent paper from Taiwan (Lung and Shu, 2007), shows for the first time in a modern sociological survey that in some places, in some cultures, the influence of mothers and fathers and upbringing can be extremely strong, though neuroticism was also important. The paper also shows that cultural factors can cause the relative importance of genetic and environmental factors to shift. In this paper I review the intellectual history of this argument, to put the Taiwanese paper in context.
A little history
In the West there have been two main sources of material on the importance of parents, one backing their importance, the other not. The first was reports from psychiatrists and therapists of what clients had found important. These went back to the mid 20th Century and even earlier. They could hardly be disputed as important to the particular clients, but they did not enable us to make statements about the population as a whole. For that, sociological surveys were necessary. The basic impression from the papers published by psychiatrists and therapists was that “smothering mothers” could be to blame, and emotionally or physically absent fathers. Sissiness, perhaps resulting from maternal over-protection, was another facet of the same family configuration.
The second source was Bell, Weinberg and Hammersmith (1981). They published results of a large sociological survey on a sample gathered by the Kinsey Institute before 1970, which contained a high percentage of homosexual people, and hence allowed statistically reliable conclusions, though it wasn’t a random sample, so we have to be a bit careful about the conclusions. They tried to make this study definitive and assembled a list of almost every social factor asserted to influence the development of homosexuality, and checked if they did correlate with later homosexuality. The results were at odds with the previous anecdotal evidence gathered by the clinicians. Each of the family factors led to homosexuality in only a small minority of cases. Other unknown factors were more important.
One possibility of course is that researchers asked the wrong questions. But in that case the therapists had also been wrong since all their suggested possibilities had apparently failed the test. Another possibility was that biological factors were predominant, not social ones, and the authors speculated that might indeed be so. A third possibility was not even considered – the predominance of individual random reactions to environments experienced in common. (Whitehead, 2007). The evidence points fairly strongly to the latter being the case.
Combining all the apparently relevant social factors Bell, Weinberg and Hammersmith were able to explain 30% of homosexuality using their mathematical model (download Chapter 11 of My Genes Made Me Do It from this website). However at one part of their book they said 30% was “Significant, and at another part “Not significant”. The contradiction between these two statements led to many subsequent writers simply stating no social factors produced homosexuality. Van Wyk and Geist (1984), pointed out this was incorrect, but were ignored. The truth is that explaining 30% in any study of this type, using this type of statistical method is common, and 30% is significant. But as to explaining most homosexuality it was indeed “not significant”. Most homosexuality was not explained.
No more studies of this extent or on this scale were done until now, and the literature, deferring to the Bell, Weinberg & Hammersmith’s paper, perpetuated the untruth that “family factors have no effect (at all)”.
Neuroticism was associated with SSA in some studies, but not others, and the general conclusion was that the association was inconsistent.
Twin studies show no social factors? Really?
Twin studies, from the year 2000 on, particularly, seemed to support the idea that social factors had no effect on homosexuality. Twin studies subdivide influences into genetic factors, environmental factors experienced in common, and environmental factors experienced by one twin but not the other. For homosexuality twin studies could not detect significant influence from common environmental factors. (Kendler, Thornton, Gilman, & Kessler, 2000; Bailey, Dunne, & Martin, 2000; Bearman & Bruckner, 2002; Santtila et al., 2008).
But twin studies conceal the level of common environmental influence in three ways. Firstly, twin studies have tended to be increasingly appropriated in the search for genetic influences, so that scientific attention has not been focused on the strength of environmental influences. Secondly: common environmental influence is actually hidden in the non-common environment category. In other words common environmental influence can be disguised as non-environmental influence because people react in very individualistic ways to a common environment. In fact the case can be made that these individualistic reactions greatly outweigh genetic influences. This point has already been made by Whitehead (2007) and in a much fuller way in another paper submitted for publication. See also chapter 10 on this website. Thirdly, and this is well established now, the twin study methodology itself (for homosexuality) tends to overestimate the genetic percentage at the expense of the common environmental percentage. See (Whitehead & Whitehead, 2007), also Visscher et al. (Visscher, Gordon, & Neale, 2008) ”…the twin literature based upon the classical twin design and model selection procedures could be severely biased…” i.e. twin studies will simply not detect common influences unless sample sizes are very large, and common influences are very strong.
Enter Lung and Shu
At this point in the debate, the paper by Lung and Shu (2007) appeared. It showed a very strong influence of parental style in Taiwan and of neuroticism, on the development of homosexuality. This was not a marginal result like so many tend to be, but unequivocal. It showed that these influences were predominant.
This seemed to contradict much of what had gone before (interestingly Lung and Shu don’t seem to have heard of Bell, Weinberg and Hammersmith, or twin studies!). Incidentally they quote a 1986 paper of Elizabeth Moberly with an additional author Phil, M.A.D. whose name appears to be constructed from her degrees MA and D.Phil……But how can the papers be so contradictory? I believe there are good reasons, and they are cultural, and shed light on the results obtained in the West.
Lung and Shu seem to be associated with the military in Taiwan and their subjects were from the annual intake of 140,000 young recruits. In that country military service is compulsory, hence the recruits represent the whole population of men. There are inevitably those who find military training almost unbearable, and many in Taiwan are diagnosed with adjustment disorder (a DSM mental health category). From these the authors selected 51 homosexuals, and 100 non-homosexuals. The controls were 124 recruits without adjustment disorder. Recruits with mental health issues other than these were eliminated from the study. It seems obvious that this study was possible because Lung and Shu were told by the authorities to study recruits who could not cope. However it means that the study of homosexuality is complicated by the adjustment disorder, which the authors had to take into account in the interpretation of their results. No other study has involved those with an accompanying mental condition like this. However it seems to me that the authors allowed for the adjustment disorder quite adequately. Overall the sample is much more representative than many in the West.
The homosexual recruits had much higher neuroticism than controls. There was no control group for this. This is a weakness in the study. We don’t know absolutely clearly whether this group were inherently neurotic and it led to homosexuality or the neuroticism was produced by interactions with their parents (which is what the authors present as the causal pathway). Regardless it is an important factor.
To give the flavour of the extraordinarily clear-cut results from the well known Parental Bonding Instrument the authors used, (a questionnaire which measures relationships to parents), I present here the results for Parental Care.
These are numbers on a scale, but you don’t need to know how that compares with the realities of the family – merely compare the numbers. The results were 13.65 ±1.00 (standard deviation) for the homosexual group, 18.07 ±0.53 for the non-homosexual group and 19.02 ±0.44 for the controls. This means the heterosexual adjustment disorder group had parental issues indistinguishable statistically from the controls (In Fig 1 the curves for both mostly overlap.) But the parental issues for the homosexual group were much, much more important. (There is no overlap at all between the curves.) In fact the homosexual group is so far separated from the non-homosexual that it represents some kind of record – a Taiwanese man (with adjustment disorder, and more neurotic than usual) is classed as homosexual or non-homosexual depending (almost entirely) only on the absence of care he received from his father, i.e. a distant father. There would be a very low error rate because the standard deviations are so relatively small. I know of no other indirect social indicator of homosexuality with such a power to discriminate. Similarly the homosexuals were found to be highly significantly deprived of maternal care, but also there was a very high degree of protection by both mothers and fathers. This seems paradoxical, but, according to Lung and Shu the general picture is of parents who are psychologically very distant, but performing their parental duties, and over-protecting the proto-homosexual by keeping him a little Mommy’s boy, and not exposing him to the difficulties of life. Allowing for the adjustment disorder, other results showed the homosexual men were also much more introverted and neurotic.
Some critics might say that selection of a group with adjustment disorder and neuroticism might also have shown the same parental factors, but no homosexuality. Perhaps, but Lung and Shu would explain their modeling (described next) is strong - but not absolute evidence - that this is not so.
Social factors explain 62% of homosexuality
In their statistical model to explain homosexuality, Lung and Shu managed to explain 62% of the variance by parental factors and neuroticism level, ie 62% of homosexuality in their sample can be explained by parental factors and higher than normal levels of neuroticism. It is quite rare to get a figure as high as this when a sociological survey is involved. The relative strengths of the factors found important were Maternal Care 0.42, Maternal Protection 0.21, Paternal Care 0.21, Neuroticism 0.64. Paternal Protection, although individually the most important, and highlighted by the authors, exerted its effect through production of neuroticism. (General mental health itself did not directly affect development of homosexuality.) Unfortunately because of the peculiarities of modeling mathematics we cannot directly add the parental factors together to get an overall effect and compare them with the neuroticism result, but we can say other parental factors and neuroticism are roughly comparable in effect.
I should add a caveat about this type of modeling. It neglects rigorous control groups in favour of using the criterion of how well the model accounts for the data, on the kind of basis “if the shoe fits, wear it”. It even assigns causes on this basis. This is not an absolute proof because the well-fitting shoe could be a coincidence, and it’s even possible that two unrelated shoes might fit equally well. This will make traditional sociologists uneasy, but when the results are as strong as those here, there is not likely to be much error.
This is twice as successful as the explanation of homosexuality that Bell, Weinberg and Hammersmith found, and has an extra fascinating implication: for the first time a careful modern study shows social factors predominate, and hence other factors, such as genetics (at least in Taiwan), must be minor!
These results support those who talk about over-close mothers and distant fathers as causes of homosexuality. Why were Lung and Shu’s results so clear compared with results from the West which were much less clear? Could the authors have manufactured their results? Are they too good to be true? I think not, because the authors seem largely unaware of the details of the controversy there has been in the West, though they understand it existed. They do not appreciate the significance of their results.
They do mention a cultural difference. They say that Taiwanese society is very traditional and conservative. This presupposes a high degree of social control, and a suppression of any genetic predispositions there might be. The role of any family factors is likely to be highly magnified under such circumstances.
I conclude that the results reflect one extreme – what happens in a society in which family influences are very strong. That itself is useful because it gives a picture of what would happen at one extreme even in the West, in social groups where only family factors are involved (the Amish?). However generally in the West things are very different. Why? Because in comparison with Taiwan we are hyper-individualistic. Our high divorce rate and extreme diversity of belief and custom are evidence of this. Hyper-individualism seems to be one of our most prized and politically-correct values. Therefore in the West even two genetically identical twins are likely to react in a different way to circumstances which might tend to trigger homosexuality.
My belief is that if the twin studies done in the West were done in a society like Taiwan (they aren't), the results would be totally different, and show a much higher contribution from common factors, and much diminished contributions from genes and non-shared environment. (This is already known for various traits – in Japan, twin studies mostly give a much lower genetic contribution than in the West). This has significant research implications. We should deliberately sponsor studies in societies with extreme conditions to get a clearer picture of influences in our own!
So for the Western situation, if some male client seems to have the pattern of a distant father, or a family dynamic which has enforced conformity and discouraged initiative and rough-and-tumble play, these factors are inherently credible, and should not be dismissed, though they will not be politically-correct. However reactions to these factors will be very variable, and individualistic.
Bailey, J.M., Dunne, M.P., & Martin, N.G. (2000). Genetic and Environmental influences on sexual orientation and its correlates in an Australian twin sample. Journal of Personality and Social Psychology , 78, 524-536.
Bearman, P.S., & Bruckner, H. (2002). Opposite-sex twins and adolescent same-sex attraction. American Journal of Sociology , 107, 1179-1205.
Bell , A.P., Weinberg, M.S., & Hammersmith, S.K. (1981). Sexual Preference: Its Development In Men and Women. Bloomington , Indiana : Indiana University Press.
Kendler, K.S., Thornton , L.M., Gilman, S.E., & Kessler, R.C. (2000). Sexual orientation in a U.S. national sample of twin and nontwin sibling pairs. American Journal of Psychiatry, 157, 1843-1846.
Lung, F.W., & Shu, B.C. (2007). Father-son attachment and sexual partner orientation in Taiwan . Comprehensive Psychiatry, 48, 20-26.
Santtila, P., Sandnabba, N.K., Harlaar, N., Varjonen, M., Alanko, K., & von der Pahlen, B. (2008). Potential for homosexual response is prevalent and genetic. Biological Psychology, 77( 1 ), 102-105.
Van Wyk, P.H., & Geist, C.S. (1984). Psychosocial development of heterosexual, bisexual and homosexual behavior. Archives of Sexual Behavior, 13(6), 505-544.
Visscher, P.M., Gordon, S., & Neale, M.C. (2008). Power of the classical twin design revisited: II Detection of common environmental variance. Twin Research and Human Genetics, 11(1), 48-54.
Whitehead, N.E., & Whitehead, B.K. (1999). My Genes Made Me Do It! Layfayette , Louisiana : Huntington House.
Whitehead, N. E. and Whitehead, B. K. (2007) My Genes Made Me Do It! 2nd Edition. Downloadable from this website
Whitehead, N. (2007). An antiboy antibody? Re-examination of the maternal immune hypothesis. Journal of Biosocial Science , 39(6), 905-921.