From time to time I reread books I have gotten on gay and other sexual matters. Recently I reread 2 books: 'Sexual Preference: Its development in men and women' (1981) by Alan P.. Bell, Martin S. Weinberg and Sue Kiefer Hammersmith and 'On the Down Low' (2004) by J. L. King. The latter book is about covert bisexuality by black men, especially those in relatively conservative churches.
Roots of sexual orientation?
The first book is significant for what it does NOT find to be scientific fact. Its authors were part of the Kinsey Institute. Their statistical studies raise much question about the credence of many psychological theories of the past, such as Freud’s theories of psychosexual development. You do not have to have a domineering mother to be gay. They say that "What causes heterosexuality?" is quite a serious question, necessary to understand how anyone's sexual orientation develops.
An often used argument for glbt rights is that these orientations are not a choice. I prefer to argue that a taboo on gay sex is a sectarian one, of no more moral worth than a taboo on eating pork. Separation of church and state! Actually there are choices we do make. I have chosen to be a Democrat, after being a Republican. I have chosen to belong to pro-glbt political and social organizations. Glbt rights are a major factor in the choices I make in public elections. I choose to express myself on dailykos.
I have long been interested in biochemistry and have followed genome research, especially about mitochondrial genomes. I cannot claim I have kept up with genetic psychology, but I strongly suspect much research remains to be done.
A gene region, called Xq28, on the X chromosome has been found to have gene variation that is correlated with male homosexuality. It is not understood whether a protein is encoded or just what this protein would do.
But are there genetic roots to sexual orientation? I seriously doubt that enough is known about genetic psychology to call anything about this matter a scientific fact. How does a mammal come to be attracted to one of the same species but opposite gender?
For many mammals the scent of pheromones plays an important part in sexual attraction. The steroid androsterone is regarded as a pheromone in male H. sapiens. Sexual orientation could depend on pheromone receptors. In 1980's a correlation with sexual orientation was suggested for the production of 2 metabolites of testosterone: androsterone and etiocholanolone, the latter with same-sex attraction. I am not aware this hypothesis went anywhere.
It is well established that mammalian brains contain mappings of the body. Could there be some kind of mapping of genitalia or other attributes of the opposite sex?
It is generally regarded that H. sapiens has no behavior that is invariant enough to be called an instinct. Every human psychological trait is subject to revision by experience. Nevertheless there likely are genetic influences.
Our genomes and those of some other mammals have been sequenced; it remains to identify genes of psychological import. It may be easiest to start with analysis of other mammals, and not just their sexual behavior. For example, different breeds of dogs show different personalities. The strategy would be to identify genes in various mammals relating to their mating behavior, then find and investigate corresponding genes in H. sapiens.
I have made some suggestions about how to research the genetics of sexual and other behavior. Comparative work could reveal human genes that are vestiges of instinctive behavior found in other mammals. I am sure that will take much work.
Bisexuality
The second book is about what American black men call being "on the down low." There are married men who furtively have affairs with other men. Often there are tragic results.
There are minsters who preach sermons against sodomy but have secret affairs with other men. The author had an affair with a man in his church. When his wife found out she divorced him.
He decided this issue needed public discussion, especially because of cases of HIV transmission. He gradually became public about his bisexuality and came to write this book.
This author writes about American black society because that is his vantage point. we should not infer from this book that bisexuality is more common among black people.
About 1970 I got to know a bisexual married man. I must clarify that both of us were white. He was a veteran of World War I.
I just wanted to be friends. He said he had never been turned down before. I take his word for it but I have often been turned down.
It seemed like a good marriage and he clearly enjoyed having children and grandchildren. I went to their golden wedding anniversary. He got me interested in being married and bisexual. He said that in my old age only my family would give a damn about me. I could see that argument but after a few years I came to conclude that I did not really want to get married.
Younger gay men would tell me I had to let my woman know I had a past. When I broached the subject to my friend he looked disturbed, said he did not think his wife suspected. I was talking to a different generation. I think perhaps she did suspect. Once we 3 were together and he said "I enjoy talking with this young man" I looked embarrassed but she smiled at me.
My friend would say “It takes a man to know what a man feels.” A woman need not blame herself if her man is bisexual. It is just some people’s nature to be bisexual. In this case I could see a motivation for the same sex. I learned something.
I could be bisexual if I wanted to be but I have thought it would complicate my life too much. Men are my strong suit.