Homosexuality may help us bond

Exploring the role that homosexual behaviour may have played in evolution: Dr Diana Fleischman

Exploring homosexual behaviour in evolution: Dr Diana Fleischman

Homosexual behaviour may have evolved to promote social bonding in humans, according to new research.

The results of a preliminary study provide the first evidence that our need to bond with others increases our openness to engaging in homosexual behaviour.

Dr Diana Fleischman, of the University of Portsmouth, and colleagues examined the relationship between progesterone and sexual attitudes to explore the role that homosexual behaviour may have played in cementing alliances over the course of human evolution.

Their research is published in the journal Archives of Sexual Behavior.

They found that heterosexual women who have higher levels of progesterone are more likely to be open to the idea of engaging in sexual behaviour with other women. Similarly, when heterosexual men are subtly reminded of the importance of having male friends and allies, they report more positive attitudes toward engaging in sexual behaviour with other men. This pattern is particularly dramatic in men who have high levels of progesterone.

The hormone progesterone is known to contribute to the formation of social bonds, which have many adaptive benefits for humans. The hormone is produced mainly in the ovaries in women and in the adrenal glands in men. It is one of the main hormones responsible for caring or friendly behaviour and levels rise when people have close and friendly interactions. Women’s levels of progesterone peak after ovulation when the chance of becoming pregnant is dramatically reduced.

Dr Fleischman said: “From an evolutionary perspective we tend to think of sexual behaviour as a means to an end for reproduction. However, because sexual behaviour is intimate and pleasurable, it is also used in many species, including non-human primates, to help form and maintain social bonds. We can all see this in romantic couples who bond by engaging in sexual behaviour even when reproduction is not possible.

“The results of our study are compelling because using two very different methods, they arrived at the same conclusion. Women were more likely to be motivated to think about homosexual sex when their levels of progesterone were higher. Compared to a control group, men’s homoerotic motivation was not increased by priming them with sex but thinking about friendship and bonding caused a measurable change in their attitude to the idea of having sex with other men.”

Having homoerotic thoughts does not necessarily mean they would be acted upon.

Dr Fleischman, an expert in the influences of hormones on the psychology of women, was studying the effect of progesterone on attitudes towards homosexuality. She questioned whether progesterone, a hormone that has been shown to increase motivation to form close bonds, might also underlie the motivation to affiliate with those of the same sex, sexually.

The researchers first developed a measure of homoerotic motivation through an online survey of 244 participants, with questions including: ‘The idea of kissing a person of the same sex is sexually arousing to me’ and ‘If someone of the same sex made a pass at me I would be disgusted’. The researchers then measured progesterone in 92 women’s saliva and found that as progesterone increased so too did openness to the idea of engaging in homosexual activity.

In the next study, the researchers measured levels of progesterone in the saliva of 59 men    before all were randomly assigned to one of three groups and asked to complete word completion puzzles, one using friendship words, one using sexual words, and a third using neutral words. Men asked to complete the affiliative/friendship word puzzle showed 26 per cent greater homoerotic motivation compared to the men in the sexual or neutral conditions. In addition, those men with the highest progesterone in the affiliative condition showed 41 per cent greater homoerotic motivation compared to high progesterone men in the other two groups.

Studies of other animals in the great ape family also point to homosexual behaviour being used to maintain and forge new friendships.

Dr Fleischman said: “Humans are among a group of animals who have sex for many reasons, not just to reproduce.  Reasons can include pleasure, a reward, a way of saying ‘please be nice to me’ or exerting dominance. It’s very complex, but it’s clear there’s a continuum between affection and sexuality and sexuality is fluidity, that is, the ability to engage sexually with those of the same sex or the opposite sex is common. In humans, much, if not most of same-sex sexual behaviour occurs in those who don’t identify as homosexual.”

The researchers will now explore other contexts and hormonal influences that could increase homoerotic motivation in men and women. They are also interested in seeing how bisexual people might react differently to social cues.

16 total comments on this postSubmit yours
  1. There’s another study to look at. It’s called the 1960’s. Everybody f***** everybody didn’t create meaningful, lasting bonds. It led to frustration, and the disolution of relationships.

    • Um, no, the 1960s was sex in order to establish a relationship, they’re talking about sex in order to cement a pre-existent relationship.

  2. As far as I know, sexuality isn’t really a continuum, at least not for men. Being truly homosexual is common enough and such a hit to evolutionary fitness that it cannot be explained in terms of increased bonding or evolutionary quirk. I can think of many other ways for evolution to increase bonding that don’t increase the risk of disease or reduce reproductive desire. You also must explain the strong homophobic reactions that most men have to homosexuals. The heritability of homophobia (about 0.4) is actually higher than the heritability of homosexuality (about 0.3)! Many hits to evolutionary fitness can be explained by pathogens and this is likely the case with homosexuality.

    • So you’re saying homosexuality is pathological?

    • R. Jones – It makes a great deal of sense that children of homophobic people would be indoctrinated to be homophobic. Homophobia is just like racism, it is solely a construct of human culture. Saying homophobia is heritable is like saying Christianity is heritable. Homosexual attraction would be heritable, according to this research, on an actual genetic basis in the sense that children would have similar levels of progesterone.

      And as a bisexual male I honestly think that all individuals who can’t appreciate the sensuality and both homo and hetero sexual relations are missing out. There’s a qualitative difference and both experiences are physically pleasurable, and i personally have felt the bonding (oxytocin) effect. We are at this point in cultural development casting off the sexually repressive institutions of organized religion so many reactionaries have jumped to the other extreme on sexuality, but you’ll all come around in the end ; ).

  3. Homosexuality doesn’t really challenge evolutionary fitness, there’s plenty of species where there are members that never reproduce but are still useful to the species. And homophobia heritable? Really? There’s little evidence to support that, it’s taught.

  4. ” Many hits to evolutionary fitness can be explained by pathogens and this is likely the case with homosexuality.”

    I agree that evolutionary fitness is shaped by pathogens (see just about every hemoglobin and metabolic disorder as a response to malaria), but I would hardly say that there is evidence that a pathogenic explanation is “likely the case the with homosexuality”.

    Do you have actual evidence that homosexuality evolved in response to pathogens?

  5. It is always important to keep in mind that the most fundamental function of sexuality is reproduction. Nevertheless, it is very clear that it is not the only function. It’s been known for a long time that sexuality in general increase bonding, no just with the opposite sex but with the same sex. We can see this clearly with the bonobo monkeys (please keep in mind that we are primates). The breakthrough in this research is not that sexuality increases bonding with members of the same sex, but the fact that progesterone may be involved. We also know that oxytocin is somehow involved as well in attachment. People in general want to think about how much homosexuality may be genetic, and certainly, there is something genetic about everything that we do and we are; however, we must think of heterosexuality somehow more linked to genetics as reproduction is primordial. Nevertheless, through the evolutionary process, it is likely that a form of ‘flexibility’ may have been unlocked to give sexuality another role. I do think it would be quite interesting to find out if the process of sublimating the homosexual drive may have some biological basis and not just cultural. I think this could be a possibility. Doing so is that quite pleasurable and common, even among people of homosexual preference. Please watch sports carefully and you will see what I mean

  6. hi

  7. This a lie from the pit of hell, God’s love is the only thing that helps us bond. The human whom God created was called human a spiritual being, no matter how you want to dress it the devil is a devil and has led many to go astray. The bible nomatter what you can say it can never change or evolve, it remains primitive and does not conform to what men think today. You cannot outsmart God in the name of psychology, philosophy, or any biological expertise. Remember you came from somewhere you may not want to acknowledge it but that’s the truth, the same way you can see a chair and believe that there is someone made it , in that simplicity take it you were created by God and the way you can best function is to study your manual, the Bible. Give yourself time go on YouTube listen a message by Billy Graham, your life will change any one of your choice.

    • “it remains primitive ”

      Really? I always thought of it as a pretty elaborate collection of stories!

    • You are hilarious! Lie fom the pit of hell indeed. Thanks for the laugh, mini-mind.

    • “Remember you all came from somewhere”
      This is very true. I came form the evolution of eukaryotic cells. As did you. As for what you believe, is your own right, aside form that your comment has little connection to the topic. If any. I suggest you find like-minded people, who truly appreciate your comments, rather than using such negative words as “hell” and “devil”. If the ‘God’ you follow teaches compassion, show a little for a different opinion than that of your own, enough so not to call something a “lie”.

  8. I suspect that it may also be the ratio of testosterone vs. progesterone (esp. in males), i.e if progesterone stayed the same, but testosterone levels fell, then we might expect the “openness” to homosexual “trysts” increase. Because findings show that testosterone levels DEcrease in all-male environments like e.g. the army or in prisons. And, surprise, surprise, so does, in prisons at least, increase the frequency of homosexual practices.

  9. Has it donned on anyone that perhaps, its not that homosexuality helps bonding… its that heteros are closed off from bonding and therefor lack what the homosexuals have….
    Because “heterosexuals” are repressing their sexuality, therefor do not allow others to truly get to know them.
    Every dominant Earth culture denounced homosexuality under threat of death to force procreation, to create more consumers and soldiers to conquer/defend lands. If only 8% of humanity experoences same sex attraction, they wouldnt have had to do that. Clearly, so many people experience same sex attraction that they had to outlaw it under threat of death to really force the issue. In this way, history supports the theory that human males by nature desire their own gender. If you look at this information through this lens, can you see what i see?

  10. Nature’s #1 goal is cast your seed into the future, or F1, F2… F infinity generation. If all species goal is F infinity, a struggle to survive occurs naturally. Nature gave species tools to overcome this struggle, adaptability (see Darwin’s Finches etc), and Family. In order for family to work, (help to attain F Infinity), we need to like our family members. A juvenile, could easily, at the opportune time, kill a sibling, so as to satisfy its needs. This behavior in the family does not help infinity.

    At puberty, sex hormones come into action, & progesterone’s kinda looses it’s dominant role to the new sex hormones.

    It’s impossible to be gay before puberty, as we have not seen the effects of the new (at puberty) sex hormones.

    I would say the strongest action for progesterone in bonding, would be:

    Mother/baby followed by sister/sister, then brother sister, brother brother, & father/child & mother father. Note before bonding between mother father a courtship ritual is displayed.

    Next Gregor Mendel pea plant seeds yielded the famous 9:3:3:1 ratio. Nowadays the 9:3:3:1 ratio is proven in Dorsophilla, by students studying genetics.

    Could the 1 in 9:3:3:1 ratio, be the phenotype GAY? And if nature has adaptability, why are gays still around? Also if one were to score, or out of the total population of, say giraffes or any other creature that exhibits gayness, how many are gay, I’ll bet it would fit the ratio.

    I would suspect, that if the sex hormones are so to speak, shunned at puberty, this would be natures, reason for not allowing that line to go forward

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