Women prefer male partners with differing MHC genes from themselves.An evolutionary explanation is that females are attracted to males with MHC alleles different from their own, to provide their offspring with a stronger immune system.Women’s fertility shapes male mating behaviour, many studies have shown that being exposed to the scent of women’s fertility led men to display greater implicit accessibility to mating-related concepts, males also judged the odours of women during the follicular phase as more pleasant and 'sexy' than odours during the luteal (non-ovulatory) phase.Hormonal fluctuation across the menstrual cycle explains temporal variation in women’s judgment of the attractiveness of members of the opposite sex.presented evidence for HLA-dissimilar alleles playing a factor in the healthiness of romantic relationships.They discovered that as the proportion of HLA-similar alleles increased between couples, females reported being less sexually responsive to their partners, less satisfaction from being aroused by their partners, and having additional sexual partners (while with their current partner). conducted an independent study on a population of American Hutterites by comparing the HLA alleles of married couples.The major histocompatibility complex genes are important for the immune system, and appear to play a role in sexual attraction via body odour.There is a relationship between various aspects of human biology and genetics with sexual attraction.
The resulting factor is that women’s partner preferences are influenced by oral contraceptives use, meaning that attraction towards an existing partner changes over time if a woman initiates or discontinues oral contraceptive use.
Body odour affects sexual attraction in a number of ways including through human biology, the menstrual cycle and fluctuating asymmetry.
It also affects the sexual attraction of insects and mammals.
Females not using non hormonal contraceptives were more attracted to the scent of males with dissimilar MHCs.
Females currently using hormonal contraceptives preferred the scent of men with MHCs similar to their own. Androstenol is produced by fresh male sweat and is most attractive to women, while androstenone is produced once the sweat is exposed to oxygen and is highly unpleasant to women.