Sexual Attration & the Female Orgasm

Currently, the majority of genetic research on human sexuality and relationships have focused on a group of genes called “HLAs.” These HLAs play an important role in our immune system and are responsible for allowing a person to fight off infections. Because a healthy immune system is vital for our survival, HLA’s have played a pivotal role in human evolution.

Researchers investigating how our genes may influence attraction and sexual relationships studied these HLA’s and found that they appear to influence body odor as well as body odor preferences (perhaps by influencing pheromones). By conducting genetic testing for these HLA genes, researchers were actually able to predict whether a particular woman is more or less likely to like the body odor of a particular man.

Additional early-stage research has gone on to find that beyond body odor preference, this group of genes may also influence and, therefore, predict sexual attraction, whether a woman is going to be faithful, whether a man perceives the woman as being sexually satisfied and sexually adventurous, and the likelihood of a woman having an orgasm with one man compared to another.

The first study to examine the way HLAs influence body odor and mate preference was conducted in Switzerland in 1995. This very interesting study had male participants wear t-shirts for two consecutive nights without washing them, after which women were given a scale to “rate” the perceived odor of the shirts. The conclusion of the study was that women found the body odor of men more pleasant if the woman and man had a greater difference between their HLA genes. These findings were confirmed with another, similar study which concluded that women found the smell of sweat from men more ”pleasant” if the woman and the man had a greater degree of difference in their HLA genes.

Researchers believe the reasons for this preference is that genetically different individuals (such as those who have different HLA genes) are more likely to produce children with a stronger immune system and that these children will be more fit to survive.

Greater diversity of genes, especially immune system genes, equals a greater chance of surviving. Basically, the least healthy children are born to individuals who are genetically very similar (such as a child who is born of incest) while the healthiest children come from parents who are very genetically dissimilar. Diversity is extremely healthy for our species and allows us to survive!

Through the millions of years of evolution, our genes have developed ways to influence us in order to ensure that individuals with very different genes are attracted to each other and have children, while also ensuring that those with similar genes are less likely to reproduce… and body odor perception seems to be one way that this has occurred.

So long before Match.com, and even before our caveman ancestors developed the ability to communicate via spoken language, our genes were working hard to bring together two people who were most likely to have healthy children. In essence, this is our body’s own built-in screening mechanism for evaluating a potential mate.

Having greater diversity in a person’s immune system increases the chances of his or her being able to fight off a wider range of infectious disease. When parents have very different sets of HLA genes, their children are likely to have a more diverse immune system and be able to fight off a greater range of infections. If, on the other hand, the HLA genes in the two parents are similar, their child will have a less diverse immune system and will be less capable of fighting off a wide variety of infections.

While today infections are not as likely to kill large numbers of people, for millions of years of our evolution they did, which is why sexual attraction based upon finding a mate who will produce children with a strong immune system was built into our genes and is still very much influencing us today.

The benefit of having two very genetically different parents has been observed for decades in laboratory animals. For example, when two genetically different lab mice (such as a mouse from North America and a mouse from Asia) have offspring, their offspring usually have ”hybrid vigor,” meaning that they are stronger, healthier, and live longer than either of their parents.

As with humans, mice are more attracted to the smell of other mice when the two of them have a greater degree of dissimilarity in their HLA-like genes. So genes controlling attraction aren’t unique to humans – it applies to influence many other species as well.

In 2006, a very interesting study conducted in the United States on heterosexual couples found that when a woman and man had a greater degree of dissimilar HLA genes, the woman was more sexually responsive and was more likely to have an orgasm with that man.

The study also found that if a woman and the man she was dating or to whom she was married had dissimilar HLA genes, the woman was less attracted to other men and also less likely to cheat. This finding was still significant even after taking into account a woman’s reported willingness to have casual sex.

As for the man, if the woman’s HLA genes were more dissimilar to his, the man felt that she was more sexually responsive and more sexually adventurous. However, while the study found that the degree of HLA similarity predicts a woman’s sexual satisfaction, the same does not hold true for men. HLA similarity predicts whether a man perceivse the woman to be more or less sexually responsive and sexually adventurous but not whether he is likely to be sexually attracted to her or to reach orgasm himself.

Interestingly, scientists found that genes could predict whether a woman was likely to be sexually attracted to, reach orgasm, and be faithful to a man only during the time of the month when the woman was most fertile (after ovulation). At other times a woman’s genes appear to have less of an influence.

Once again, on a purely evolutionary level, this makes sense – the primary goal of genes impacting sexual attraction isn’t pleasure; it is to ensure the conception of a baby with a healthy immune system. This is why it appears that only when they are fertile will women have an attraction to men that are more genetically different from them.

It is most likely that genes play a role in a woman’s ability to reach an orgasm because the female orgasm creates muscular contractions in the vaginal wall that have been shown to help retain sperm, thereby increasing the chances of conception.

When a woman has a dissimilar set of HLA genes compared to a man, she is more likely to be sexually attracted to him and more likely to reach orgasm, and the orgasm increases her chances of getting pregnant. This, in turn, leads to a greater likelihood of conceiving a child that has a diverse set of HLAs and is, therefore, better able to fight off infections and survive.

The research discussed above takes genetic testing and the science of relationships and dating to a new level. Existence Genetics can provide straightforward testing for the HLA genes of a man and woman and tell the woman whether, during the time of the month when she is most fertile, she will be more or less likely to be attracted to, have orgasms with, and be faithful to, that man compared to other men.

Existence Genetics can also provide insight for the man as to whether he is likely to perceive a woman as being more sexually adventurous and sexually satisfied when she is with him.

It’s important to understand that our genes are just one component in determining sexual attraction, orgasms, faithfulness, and perceived sexual satisfaction and sexual adventurousness. Because of this, genetic testing cannot provide definitive information. It cannot, for example, definitively say whether a woman is going to be able to reach orgasm in general. But it can provide insight into whether she is more or less likely to reach orgasm with a specific man.

If you are interested in learning more about this unique type of genetic testing, please email info@existencegenetics.com.