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Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men

Abstract

Androphilia is associated with an elevated number of older brothers among natal males. This association, termed the fraternal birth order effect, has been observed among gay men who exhibit marked gender nonconformity. Gender nonconformity has been linked to gay men’s preferred anal sex role. The present study investigated whether these two lines of research intersect by addressing whether the fraternal birth order effect was associated with both gender nonconformity and a receptive anal sex role (243 gay men, 91 heterosexual men). Consistent with previous research, we identified the fraternal birth order effect in our sample of gay men. Also, gay men were significantly more gender-nonconforming on adulthood and recalled childhood measures compared to heterosexual men. When gay men were compared based on anal sex role (i.e., top, versatile, bottom), all groups showed significantly greater recalled childhood and adult male gender nonconformity than heterosexual men, but bottoms were most nonconforming. Only gay men with a bottom anal sex role showed evidence of a fraternal birth order effect. A sororal birth order effect was found in our sample of gay men, driven by versatiles. No significant associations were found between fraternal birth order and gender nonconformity measures. These results suggest that the fraternal birth order effect may apply to a subset of gay men who have a bottom anal sex role preference and that this subgroup is more gender-nonconforming. However, there were no significant associations between fraternal birth order and gender nonconformity at the individual level. As such, based on the present study, whether processes underpinning the fraternal birth order effect influence gender nonconformity is equivocal.

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Notes

  1. Recent research suggests that only-child gay men might owe their sexual orientation to maternal immune processes that are not related to the fraternal birth order effect (Blanchard, 2012; Skorska, Blanchard, VanderLaan, Zucker, & Bogaert, 2017; VanderLaan et al., 2015). As such, we also performed our analyses with only children removed; however, doing so had no impact on the statistical significance of the findings reported here. We, therefore, present the analyses with only children retained.

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Acknowledgements

We would like to thank all our volunteers who assisted in participant recruitment at the Toronto Pride Festival (Mary Loka, Lindsay Melhuish, Phil Nguyen, Lauren Oakley, Martha Pokarowski, Firyal Ramzan, Anna Takagi, and Robert Wither). The research reported in this article was supported by a doctoral Canada Graduate Scholarship from the National Sciences and Engineering Research Council of Canada (NSERC) and an Ontario Graduate Scholarship to ASG, as well as by NSERC Discovery Grants to DAM and DPV.

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Correspondence to Doug P. VanderLaan.

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Swift-Gallant, A., Coome, L.A., Monks, D.A. et al. Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men. Arch Sex Behav 47, 1041–1052 (2018). https://doi.org/10.1007/s10508-017-0980-y

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  • DOI: https://doi.org/10.1007/s10508-017-0980-y

Keywords

  • Sexual orientation
  • Birth order
  • Maternal immune hypothesis
  • Gender nonconformity
  • Anal sex role