from What do clinical studies say?
Previous studies found a "fraternal birth order effect"--the Danish study found nothing-- and the McConaghy study contradicts them both!
By N.E.Whitehead, Ph.D.
Lower Hutt, New Zealand
Is there a "fraternal birth order effect" (FBO) that makes some boys more likely to become homosexual? This theory is explained by the researchers in this subject with the "maternal immune hypothesis," which argues for an immune attack within the mother's uterus on her male fetuses which later causes them to develop SSA (same-sex attraction).
New studies on people with predominantly opposite-sex attraction (OSA) mixed with some same-sex attraction (SSA) are challenging this popular belief that FBO affects male sexual-orientation development.
Looking At OSA Males With Some SSA
There are far more OSA people who are tinged with SSA ("nearly straight") than there are SSA people tinged with OSA. For example, in Australia, perhaps as many as 20% of the population are "nearly straight," as compared with 2% who are same-sex attracted with a tinge of opposite-sex attraction (McConaghy, et al 2006).
This finding is hardly surprising, because the "nearly straight" group could include those many persons who have only briefly experimented with SSA. But the really significant group, for purposes of study, is those people currently active with both sexes. Pathela, et al. (2006) report on this group in a New York setting.
They find that 10% of their sample identify as straight, but sometimes have sex with men. This group may be a little atypical; it is highly urban and contains an unusually high proportion of foreign-born subjects. However, it is clear that these "nearly straight" men are the most common group of those who report "at least some SSA," though it is doubtful they are often found to be seeking therapy.
It sounds quite bizarre that people would identify as straight but have sex with other men, but, of course, prisoners tend to do this. Such a discordance between identity and behavior could be due to a variety of reasons. Even among non-incarcerated men, some homosexual activity is likely engaged in just for the sex--because a male partner is much more readily available, "dating" is not required, and requires less commitment than a woman.
When sex is sought "just for the sex," then some of the childhood family dynamics (distant father, over-involved mother) that NARTH therapists encounter in SSA men may not be found in this "nearly straight" group.
Australia seems to have a particularly strong tradition of research on this group, going back to the '80s with the work of Ross. This research seems to have been the result of an active national concern about the possibility of AIDS being spread to the OSA community through those who are married but sometimes have sex with men. The fear was that they might be infected, never use condoms with their spouses, and pass on that infection.
Australians believe they have done a better job preventing infection among this group than most other countries. However, "nearly straight" men remain unusually vulnerable to infection because of their na´ve safe-sex assumptions.
Among exclusive gays who are HIV-positive, when another man initiates unprotected sex, they usually assume that the other man must also be HIV-positive. On the other hand, someone married but with some SSA, assumes that another man initiating sex without protection is like himself--i.e., non-infected. Thus there are compelling social reasons for keeping the two groups apart! Social workers try to reinforce this message.
An interesting, though mostly anecdotal book on the subject, is She's My Wife, He's Just Sex by Australian author Sue Joseph (1997). The author is a journalist and conducted wide-ranging interviews, including with coordinators of a support group for "nearly straight" married men. The group coordinator helps them clarify their values and the consequences of their various choices. Among members of this group, she often found their motive to be simple curiosity as to what sex with another man might be like. These men identified as straight, disliked the culture of the gay community, and stayed away from it. "Beats" or cruising areas (there are 60+ in Sydney) tend to specialize, and some are for married men only; this was one reason why infection was not common among them.
Recently, an interesting paper from Australian researchers McConaghy et al (2006) has appeared, dealing with this same group of people - those who have OSA tinged with SSA - but women were included as well.. Up until now a score of papers researching predominantly the gay community have shown that elder brothers increase the probability of SSA by about 30% per brother. (This was never found for lesbians.) The salient point is that McConaghy's study seriously questions the usual pattern of the FBO effect that suggests a biological foundation for SSA.
The FBO effect has been found in a few careful representative samples in the general community, so it appeared to be a robust finding. However, as reported in the last NARTH Bulletin, a Danish study (Frisch and Hviid, 2006) could not find the FBO effect in a sample of 2 million Danes. That might be the result of the fact that their criterion of SSA was formalized (homosexual) marriage, which might represent an atypical class of SSA men. But the McConaghy paper looked not at the 2% of SSA people with an OSA tinge, but at "nearly straights"--OSA people with an SSA tinge.
To everyone's surprise, McConaghy's result was a dramatically different pattern from previous studies. The sample was based on Australian medical students, like most of McConaghy's previous papers. It showed, as the earlier papers had, an older brother effect--thus far, no surprises. But (for the first time) there was also a weaker older sister effect for males with SSA. This is quite different from earlier findings, because according to the theories, elder sisters should have no effect at all on SSA. Even more damaging to the theory, and another first, was the finding of an older brother effect for women with SSA. Women have previously shown no elder-sibling effects at all, and according to the biological interpretations, never will. The strength of SSA feelings was not significantly related to the number of older brothers--the trend was in fact, slightly negative. This also is contrary to a biological explanation, because the strength of SSA feelings should increase with each elder brother.
McConaghy replicated his result with other groups of medical students. The authors therefore said there must be a social explanation rather than a biological one, and this raises serious questions about the FBO effect--just as the Danish study did.
In summary, the traditional studies found an FBO effect--the Danish study found nothing--and the McConaghy study contradicts them both! Whatever the explanation of these findings (and it is possible to imagine explanations from sibling and family dynamics) they don't look biological. The researchers do acknowledge that their findings need replication by independent researchers.
The Maternal Immune Hypothesis
The FBO-SSA link is often explained using the maternal immune hypothesis, which argues for specific immune attack by mothers on male fetuses. But the authors of this paper say their results are quite inconsistent with this immune hypothesis.
It is still possible that the SSA-tinged OSA subjects are yet another special case, and some biological explanation is involved, but the varied explanations for the different and rather contradictory findings are beginning to sound like special pleading.
What could be the explanation for these contradictions? It is increasingly likely that (yet again!) accidentally biased sample groups from the GLB community have been used in older studies.
Therefore, a biological explanation looks less and less likely.
Frisch, M. and Hviid, A. (2006) Childhood family correlates of heterosexual and homosexual marriages: a national cohort study of two million Danes. Archives of Sexual Behavior 35 (5):533-547
Joseph, S. (1997) She's My Wife, He's Just Sex, Sydney: Australian Centre for Independent Journalism, University of Technology.
McConaghy, N., Hadzi-Pavlovic, D., Stevens, C., Manicavasagar, V., Buhrich, N. and Vollmer-Conna, U. (2006) Fraternal birth order and ratio of heterosexual/homosexual feelings in women and men. Journal of Homosexuality 51 161-174.
Pathela, P., Hajat, A., Schillinger, J., Blank, S., Sell, R. and Mostashari, F. (2006) Discordance between sexual behavior and self-reported sexual identity: a population-based survey of New York City men. Annals of Internal Medicine 145 416-425.