Thanks for posting this. Unfortunately, epigenetic models will be even harder for some to wrap their heads around than simplistic, single gay-gene models. The connection to in utero developmental interaction with testosterone is certainly a likely place to look!

What's the odds of that?

maybe both parents carried the marker.

I guess lightning can strike twice in the same family. The theory sounds reasonable to me. My wife is as straight as an arrow, where as I have had some bisexual adventures. It would make sense that my daughter ended up with my tendencies, however she seems to be pure lesbian.

But I have wondered about identical twins who differed. I think the answer is more complex than simple and there is more to any theory about anything, even gravity has differing theories about certain properties.

The one thing I would not like to see is identifying which parent passed the marker, there are enough disagreements in families without "blame" for acceptable behavior.

Also, I don't like "gayness" as masculinization of females or feminization of males. It is far more complex. In my fantasy simple world, I don't understand why people can't just love the person whatever sex they happen to be.

enough of me talking about stuff I am ignorant of.

I have a daugher who is type 1 diabetic. The odds are 1/2 of 1% that anyone will have Type 1. Identical twins, who carry the same genes, only have about a 20% chance of becoming diabetic if their twin does, so there is something else involved as well. Not sure how this relates to your post hollysmom, but it struck me as interesting.

I have to assume that is why I never understand.

For example, I had read left-handedness might be due to a small lack of oxygen to the brain at a specific point in the birth process. Perhaps the epi-genetics are necessary, but not sufficient, and it takes a similar minor "birth trauma" to really kick in.

It might be worthwhile to study the incidents with identical twins and see if there is any correlation with being first or second in birth order, or a more or less difficult birth, and being gay.

is that caused through a lack of oxygen as well?

My ex came from a family of left handed people, maybe that was custom.

And when I say I don't see why there should be righthandedness, I mean in preference to ambi dextrousness. Like, I am ambifooted in an odd way, As I child I read a book about a woman who painted with no arms, she used her feet, so I decided to learn to write with my feet. it is not elegant or small, but equally legible with both feet, each equally unelegant. However I do start walking with my right foot, but that was probably learned in gym class with all the marching.

suggested a gay person was likely to help raise their nieces and nephews, and so while they themselves might not reproduce, they helped with the overall survival of relatives. So if there's a genetic marker of any kind, then it would tend to remain.

I kind of think the estimate of what percentage of people are gay or lesbian is a pretty stable one, no matter how enthusiastically the expression of gayness is suppressed. I don't know offhand what that percentage might be.

Identical twin studies are always interesting, because so many strongly genetic things like certain diseases often happen to one twin but not the other. So clearly there is almost always an environmental trigger or interaction.

It is a means of genetic population control, essentially. Although I do take issue with the researcher's usage of the words feminization and masculinization, that is simply not the case. It is time we look at sexuality in terms greater than simply as being sex based. It is gender based.

It is hard to tell if this is just bad writing by an alleged "science" writer, or cluelessness on the part of the researchers, the writer, (or both). It all seems to be based on a series of unfortunate (and erroneous) assumptions. Someone doesn't seem to know much about how evolution works, "homosexuals", twin studies, and who knows what else...

These scientists have a speculation (not a theory), but no, the idea that some mechanism outside of the genetic code explains how it could bypass evolution doesn't work. If homosexuality wasn't an evolutionary advantage, then it wouldn't exist, evolution would eliminate it. Whatever the alleged mechanism, genes, prenatal hormones, "epi-marks", that just begs the question. If epi-marks or hormone malfunctions were maladaptive, evolutionary processes would eliminate them. "scientists would expect the trait to eventually disappear because homosexuals wouldn't be expected to reproduce" - a big assumption, unproved and erroneous - anthropologically speaking, it doesn't take into account kin selection, demographic factors, and human societies and culture and religion, let alone humanity and intelligence. As for culture, in most societies most gay people do and did marry and have children. For example, in an extremely homophobic group like the mormons, children were expected to marry and have lots of children. Gay children didn't have a choice, they married and had lots of children. If anything, this would have have increased the percentage of gay genes in the population...

It is not a "puzzle" that some people are capable of homosexual behavior. Homosexual behavior has been observed in almost every species, so it would only be a puzzle if humans didn't do it also. The study purports to only give a reason for homosexual behavior in humans, without accounting for this being normal in the entire animal kingdom. The idea that this is a puzzle is absurd. Even flatworms have a more complicated sexuality than some "scientists" can conceive that humans could be capable of. But humans are the most complex creatures on the planet.
They also seem to be carelessly conflating sexual orientation with homosexual behavior. Human traits and behaviors are all much more complex that that. Maybe the "scientists" talk about "homosexuals" as if they are a specimen of bacteria on a glass slide, but the writer compounds the insult, as he with facile disdain easily dehumanizes gay people by calling us homosexuals in most of the article. No, we are gay PEOPLE, so when you are referring to gay people you say gay people, you do not talk about us like we are a thing under a microscope - this is not a clinical paper, this is an article written for people to read.
By the way, what about bisexuals? Are these scientists assuming that there are only heterosexuals, except for that small group having this puzzling gay anomaly? They always forget that the vast majority of people are bisexual to some degree.
Don't get me started on twin studies. I could write a post on that all by itself.

And this set of assumptions is just laughable: "excess or underexposure to testosterone — when they carry over to opposite-sex offspring, it can cause the masculinization of females or the feminization of males," Really? Sounds like a homophobic 1950's psychologist's wet dream fantasy "theory". That's speculation, prove it, prove that it has those alleged effects... "Rice says, which can lead to a child becoming gay". Really? Hormones make you gay? Gay men are feminized males? Seems like these scientists think of gays and lesbians as 1950's sterotypes. All gay men are Liberace...

In essence gay offspring are the result of poor biological housecleaning when epi-marks are not removed but are passed to the children.

That's how I read the article.

here is that part:
"because these epi-marks provide an evolutionary advantage for the parents of homosexuals: They protect fathers of homosexuals from underexposure to testosterone and mothers of homosexuals from overexposure to testosterone while they are in gestation."

What is the evolutionary advantage to the parent? that the father or mother didn't become homosexual? What good is that if it only leads to having a homosexual kid instead? Either way, it is an evolutionary dead end, if as they are claiming, that the homosexual offspring are not breeding, and there is no evolutionary advantage to that.

and therefore don't have homosexual kids.

The evolutionary advantage to the parents is they are predisposed to mate and reproduce.

"because these epi-marks provide an evolutionary advantage for the parents of homosexuals"

whatever, I think whoever said that was just confused...

Anyway, as you said, most parents don't pass on the epi-marker, resulting in more heterosexuals...

But, the other parents do pass on the epi marker, allegedly resulting in gay kids... Those parents are at a reduced fitness compared to other members of their species that don't have this epi-mark problem. Those parent's genes would be outbred over time by their competitor's superior genes.

As I said above, that is how evolution works. Natural selection would eliminate the propensity to pass on epi-marks, and the epi-mark weakness would be eliminated from the gene pool.

Of course, it is all pure speculation that these epi-marks even exist, or that they perform the function of manipulating the genes as the scientists postulate.

it is an evolutionary advantage to every human. But in most humans the epi-mark is removed and not passed on to offspring.

or is it balderdash ?

That doesn't change that we are born this way. I certainly didn't choose to be a lesbian as a fetus.