Influence of Human Leukocyte Antigen on Olfactory Sexual Attraction in Non-Heterosexual Brazilian Men.

Body odors influence immediate sexual attraction and are affected by a key genetic component of the immune system, the human leukocyte antigen (HLA). This relationship is important because evidence suggests that reproduction with partners who have dissimilar HLA leads to offspring that are more resistant to pathogens. However, research typically focuses on the effect of body odor on partner selection among heterosexual individuals. In this study, we analyzed the influence of HLA on olfactory sexual attraction in non-heterosexual Brazilian men. A total of 40 men (20 non-heterosexual and 20 heterosexuals; average age of 31.4 years) evaluated the axillary odors of other men with different sexual orientations. The results showed that men rated the odors of other men with similar HLA as more intense, regardless of sexual orientation. We found that non-heterosexual men rated the body odors of other men as more attractive, regardless of HLA similarity. Additionally, non-heterosexual men rated the odors of other non-heterosexual men and of men with similar HLA as more intense. Our findings indicate that HLA similarity does not influence olfactory sexual attraction in non-heterosexual men, suggesting that this pattern is more affected by sex than by sexual orientation. These results reinforce the role of HLA in odor detection but not in odor preference. This study contributes to a broader and more inclusive understanding of human sexuality, highlighting the complexity of mechanisms involved in sexual attraction.