I think the assumption that the existence of homosexuality being driven by an evolutionary process through genes is somewhat misplaced. Otherwise, one would expect that we would see clusters of homosexuality in particular families.
I’ve read somewhere that the incidents of a homosexual son are significantly more prevalent in the third and subsequent son of a mother, suggesting hormonal influences based on the mother’s mental and physical condition.
Someone mentioned earlier about Downs Syndrome which is riskier when the mother gets older. I mention this merely to provide the reason that the condition of the mother is a factor, rather than genes.
After all, there is no evolutionary driver to produce DS is there ?
Correct me if I’m wrong, but isn’t that exactly what we do see? If a person has close family members who are gay, that person is more likely to be gay than a member of the general public. It’s not absolute (identical twins can have different sexualities), but there’s at least a genetic component.
Wild-assed guess by a non-scientist: watch me embarrass myself:
What if heterosexuality was the mutation? Maybe animals (including humans) started out as bi-sexual or omni-sexual. And the prevalence of heterosexuals in our day and age simply reflect the advantage heterosexuality had on the propagation of the species.
(Please be merciful as you rip my lazily-formed hypothesis to shreds
Again - this really isn’t a big mystery, and I know what I’m talking about. I wish people would quit acting like it’s some big thing waiting to be solved. If anything, it’s probably irrelevant from an evolutionary perspective.
Even if it were genetic, I have trouble believing homosexuality has even been remotely acceptable enough in any of today’s societies long enough to study it and rule out social factors (e.g. people from the same families having the same views on homosexuality – bigoted enough to be terrified of coming out of the closet, or liberal enough to be openly gay). Can anyone alive today point out homosexuals in their family tree? Even in my parents’ generation, they didn’t have gay uncles or grandmas, they had relatives who ‘lived with a roommate’ or who were shunned completely.
As far as the evolutionary effects of homosexuality, the genome cannot have changed quickly enough for social pressures to alter the incidence or heritability characteristics in the very brief time that humans have had cultures widely enough spread to affect the whole species.
Sexual behaviors are not genetically significant except where they affect success rates in producing offspring, and many types of socio-sexual relationships make transmission of even a dominant homosexuality allele group unlikely to be affected by any practice other than exclusive homosexual monogamy by the majority of those with the allele group. That specific behavior is not recorded in any case that I know of.
Although you cannot have offspring by your homosexual mate, both you and your mate are eligible for procreative success outside of the mate bond, and promiscuity of all types (voluntary, and involuntary) is a fairly reliable human characteristic. Given the huge social pressure toward success in producing heirs in early cultural models, exclusive homosexual monogamy is unlikely to be absolute, nor even particularly esteemed. Occasional, or even non-exclusive homosexual behaviors were not so universally condemned as some would prefer to believe, nor was heterosexual promiscuity uncommon in any era of human history.
The genetic element actually present in homosexuality is certainly not imperative, and societies that have had less rigid codes of conduct with respect to homosexual liaisons often include social recognition of paramours of either sex. However, as noted in my first statement, society is a trivial element of human genetics.
I’m sure they do – just like the mother’s body tries its best not to produce blind, deaf, or sterile babies, or babies with a hole in its heart. It still happens though. You can make the same embyro in the same womb 100 times and have slightly different outcomes each time.
And even if homosexuality was all in the genes, the answers would either be it’s not as disadvantageous as one may think and/or it’s impossible to fix given our spot in genetic space. Apparently this applies to most other animals as well, so we’d have to go back a long time in evolutionary history to tackle it. Just like many other strange artifacts in our body.
It’s not necessarily disadvantageous, especially in the context of third- and later children, where it seems more prevalent.
Not all advantageous mutations confer a direct benefit. Consider, say, lions: when a bachelor male successfully challenges an alpha male, and thus inherits his pride, he may kill off some or all of the juveniles fathered by the incumbent. That’s not good for lionkind, but it’s apparently useful to his own offspring.
Now, consider pre-societal (and, in fact, pre-modern) breeding patterns in humans. We had a lot more kids, and developed fairly tightly structured family arrangements to provide protection and care for young beyond what parents could offer alone.
Now, picture a new homo mating pair - taking care of two offspring is doable. Taking care of three? Difficult. However, what if in your extended family you could be guaranteed two or three otherwise healthy individuals able to care for offspring and guaranteed not to produce their own?
Wow. That was a remarkably sensible and lucid post.
Really? It raises the temperature of the body. It was an adaptive response to the cold of the Artic. It’s also an attempt by the body to raise the metabolism.
As for the orgional topic…maybe the reason homosexuality exists is so that people can exist and contribuate to society without contribuating to overpopulation!
The best documented genealogy on Earth is probably that of the royal family of England. They’ve had several gay or bisexual ancestors in their direct line, both direct and collateral, dating back at least as far as the 11th century (William II Rufus) and including several others in the direct line (most famously perhaps Edward II and James I/VI). Some of the grandchildren of Eleanor Roosevelt accept her lesbianism (others deny it or say the perfectly acceptable imo ‘none of your business’) and of course Oscar Wilde’s grandson and great-grandchildren can’t much deny it. So yeah, there are plenty of people who can point to confirmed homos in their lineage.
But yeah, it’s true that more often are the people who had roommates for 25 years in spite of no financial need. Most of the stories about great-grandma and the preacher’s wife or Uncle Herbert and the florist who got him thrown out of the Elks Club tend to get intentionally forgotten.
Point of order: For the purposes of this exchange (assuming that it is followed up), is everyone on board with genetic basis being an interchangeable term with genetic component?
I think we need to get that clarified before people start talking past one another.
ETA: P.S. James I/VI? I knew the British monarchy had some . . . idiosyncratic habits, but I had never heard of numbering their lineages with fractions.
The percentage of population is undoubtedly underreported. There are huge societal pressures in most parts of the world for people not to live openly. I would wager that even in this country in this day and age there’s more in the closet than out, but how do you quantify it? Unless we miraculously isolate “the gay gene” some day, all we can really say is who is living openly out (or willing to admit the truth to themselves and statistitians).
To me, this says that gay people who have other family members who are openly gay are much more likely to live openly themselves, which makes sense.
He was already the King of Scotland when he ascended the English throne, uniting the two countries. In England, they’d have five previous Jameses, but in Scotland, he was the first monarch of that name.
I read that males born after many brothers are likelier to be gay, the mechanism being that the mother builds up some kind of defense against male fetal hormones and releases more female hormones.
I wondered if this might provide helpful, strong contributors like the Queer Eye stars in situations where there are already more males around than breeding requires. Populations with this mechanism in them would generally do better in reproducing because of the helpfulness, though the individuals born after many brothers who actually trigger the mechanism would not reproduce especially more often.
Yes, this is the best evidence we have so far for a biological link to homosexuality. The increase is slight, though, so it’s not like you’re more likely than not to be gay if you have 4 older brothers.
I won’t speculate as to how things started out, but bonobos – who are, along with chimpanzees, the living primate species most closely related to humans – are bisexual in their behavior. Bonobos do not form exclusive sexual pairs and engage in frequent sexual activity with both same-sex and opposite-sex partners. This sexual behavior serves a social role even when it is non-reproductive. Bonobos tend to feel more friendly towards other bonobos with whom they’ve had sex, and they also engage in behavior that seems very similar to human “pity sex” and “make-up sex”.
