Genetic question related to Homosexuality?

Question

I was just reading on a philosophy web page and a topic had to do with homosexuality. This question has NOTHING to do with it being right or wrong or anything of that nature. I want to ask one thing and one thing only. I had never thought of this and I lack the biology to explain it. It was brought up in the thread and Im very anxious to understand.

If Homosexuality is genetic (I believe it is. If you dont, dont reply to this because it makes my question pointless. I only want answers assuming it IS genetic otherwise my entire question is meaningless) how is it passed on? Homosexual individuals will not procreate so how can their genes be passed on? This also applies to horrible genetic diseases. If the individuals with it die, how are those diseases still around? (Surely they will reproduce before dying, but not as much as others. The carriers of the disease will eventually die out)

Im assuming maybe each homosexual person is a specific mutation and is not heritable? Please help!:)

Just to clarify: Please dont respond saying "Its a choice" or other such comments. They are pointless. Secondly, as Im sure all people reading in the biology section know, I meant mutation in a purely scientific way. Im not hinting at the idea that homosexuals are "mutants" in some derogatory sense. Sorry to be overly cautious but you have to be carefull and mindfull of people's feelings when talking of certain topics.

Answer 1

I personally See a Predisposition as Polygenic, but Essentially a Continuum of Sexual Response, "Homosexuality", as a Mixture of Nature and Nurture.

Answer 2

Homosexuality should not be thought of as an either or situation, but instead a gradient. Few people have only straight or only homosexual tendencies (not just sex but sexual thoughts or acts not limited to intercourse). Our society does not accept homosexual behavior very well (as much as we like to say "no that there is anything wrong with that" we dont like the idea for some reason). Many homosexual encounters are not discussed, therefor you do not think of the person as having these experiences. I know of a few men that were married and have children, then came out when they were in their 50's. Also, college is known as an experimental time for sex. Most of this is not considered in later life. On the other side, many homosexuals struggle with their identity when they are first realizing they are gay. Some even go and try the straight route a time or two to see how they really feel.

Bisexuality is much more prevalent than that is typically thought. So, there are infact many oppertunities for a "gay gene" to be passed to the next generation.

Answer 3

There is the so-called "Uncle" theory which can explain how the homosexual "gene" is passed on and maintained within populations.

Assume a man is homosexual and does not sire any children during his life; therefore, none of his genetic information will be passed on to a new generation. However, he may have heterosexual brother and sisters. They will be approximately 50% genetically identical to the homosexual man and some will probably carry the homosexual gene even if they are not themselves gay. Any children that they have will have 25% genetic identity with their gay Uncle and may again pass on the homosexual trait to their offspring. Although the gay uncle does not therefore contribute directly to the next generation's genes, he does so indirectly through his nieces and nephews. Moreover, if he is active in helping to raise and nurture his nephews and nieces and ensure their survival he increases the chances of his gay gene being propagated in future generations. Some theorists believe that gay Uncles may be gentler and perhaps more feminine than straight Uncles which is why they make better Uncles and better carers/protectors for their nieces and nephews.

The part an Uncle plays in raising his nieces and nephews may be reduced in today's modern world but in primative hunter gatherer societies (and even 100 years ago when we all lived as closer family units) an Uncle may have played a much greater role in protecting his brother or sister's children until they reached adulthood and had children of their own.

Homosexuality is therefore a desirable thing for a society to have if Uncles ensure survival of the next generation, and in doing so they ARE actually ensuring that any "gay" genes are passed on to the next generation.

Answer 4

Of course not it is not genetic it is hormonal. We all start a female only if the sperm that enters the egg has a xy chromosome do we start becoming male and that process can be faulty for all sorts of reasons. and the fault can lead to homosexuality, transsexualism or transvestism. There are known cases of girls being born and growing up unable to have children and when this is investigated it is found that they genetically male but that they did not react of the testosterone in the womb so while they look female what appear to be ovaries are in fact undeveloped testes and what appears to be a clitoris is in fact an undeveloped penis. You are dealing with a vast a complex subject and if you are really interested you should start reading the books. BrainSex is a good readable one Amazon with have a copy

Answer 5

Hi
I think your question is very interesting! Well in terms of genetic disorders, people don,t always die! They are often passed on even if the disorder is dominant. With regards to homosexuality, the question becomes a little more difficult. One possibility is that people have a genetic predisposition to be homosexual, but require the environmental cue for the phenotype to develop. This is the case with many cancers, heart disease etc...
In this way homosexuality can be regarded as an unadvantagous mutation (as it prevents reproduction)

As far as I am aware no genes have yet been identified for same sex preferance. With the development of homosexual phenotype, however, the morphology of brain structures critical for emotion change slightly. This is as a result of the actual behaviour, not genes.

Answer 6

I'll just throw this into the mix for consideration, as I don't know if it means anything, or not. At the outset, the external sex organs of a baby [for both male and female] are female. Only after 19 or 20 weeks can a doctor use ultrasound pictures to be able to see the male sex organs developing, if it will indeed be a boy. Could this make a difference somehow in later sexual orientation, if a "hitch" occurs during the first 20 weeks? Think on it.

Answer 7

Hey! Interesting question. First off, I'd like to say thanks for being so mindful of others by framing your question so thoughfully and honestly.

Recently, there's been a lot of research about homosexuality, it's genetic and environmental basis. There are tons of influences that affect the development of a human being from a blastocyst with only a few hundred cells to a walking talking person like you and me.

Turns out, very few characteristics are determined purely by genes or purely by environment. More often, characteristics are determined by gene expression in combination with environmental influences. DNA has a huge influence on a variety of characterisics people develop. In gene expression, there is lots of regulation through chemical modification that can be affected by one's environment.

Most recent research suggests (does not prove) that pregnant mothers produce certain horomones in their bodies that affect embryonic growth. For some reason, it seems this horomone or combination of horomones is produced when the mother is under some sort of stress. When the horomone is produced, children tend to be homosexual. Personally, I find it interesting that although homosexuality is not a choice, it is not entirely determined by one's genetic information.

On a side note, it makes sense that the mother would produce homosexual children if she were under stress. It seems like homosexuality could be nature's way of population control.

Answer 8

I would be a little reluctant to accept information regarding homosexuality that was the product of philosophical enquiry. I don't know what "thinkers" have to say about global warming, but I would be rather more inclined to rely upon scientific data than upon deductive reasoning for any information.

It is a well established fact that these matters are often, in some sense, choices, but choices so powerfully conditioned by life experiences that they scarecely merit the name choice. Individuals who are abused as children often are for the rest of their lives confused about gender matters, and choose homosexual relationships. Psychiatric studies seem to indicate that very strong mothers married to passive men often produce one or more gay son. These cases are not genetic in any way.

On the other hand, instances of females who have very clear and pronounced male characteristics are all around us, and males who are genetically morphed as females exist on the same scale. These cases had no choice.

I have a woman friend (lesbian) who has larger hands than mine, and can out-run me and probably could pound me to a pulp were she disposed to do it. She did not choose that mind and body she was born with.

I have a gay pal, a Latino and a bear-type, and I could have predicted his parents even before I met his dominating mother and the father who never could protect him from her.

I am straight, but I am also a reasonable man, and homosexuality is not in every case genetically determined. I am unwilling to leave your readers with your assertion regarding the point.

Answer 9

There have been scientific studies that have proven homosexuality is a chemical imbalance in the brain; My theory is it is a recessive trait and that some individuals do not display homosexual traits or try to hide it by having marriages and fathering children there by passing on the gene.

Answer 10

It has been said that a child's sexually comes from the mother. She carries some kind of gene that can be passed to the child and when they are born they are born homosexual. I honestly believe that is a way a person is born not by choice. Sometimes dieseases skip generations or parents can carry a dormat gene and not know it.

Answer 11

I have a couple theories about this. One or none may be right. Or maybe they are partially right.
1) It's a recessive trait. Each person has 2 genes for each trait. One from their mother and one from their father. If we have H = heterosexual and h=homosexual, then a person may have gene combinations of HH, Hh, and hh. HH and Hh would be heterosexual because H is dominant. Only hh would be gay because they don't have an H to dominate over the h gene.
If one of the parents is HH, they have no chance of a gay kid.
If both parents are Hh, they have a one in four chance of having a gay kid. Their kids would be HH, Hh, hH, or hh.

This is an oversimplification of genetics because there could be multiple genes involved or the phenotype (the traits expressed physically) could be attached to another gene like the sex (gender) gene as baldness largely is.

2) Another possibility is that homosexuality is partially genetic. That is, the gene makes a person prone to being gay if the "right" things happen to them in their life. For example, if they didn't feel close to other males in their childhood. One child that is not genetically susceptable being gay will grow up heterosexual and the another that is genetically susceptable to being gay will end up becoming gay.
If the genetically suscpetable person does feel close to other males in childhood, then they grow up to be heterosexual.