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Homosexuality, could it be an anomaly in brain developement? Dr. Nick Riviera 15/02/05(Thu)04:59 No. 16039 ID: 8ec688

File 14231087868.png - (64.35KB , 320x307 , Dr__Riviera.png )

Hi guys, to begin I just want to make a couple of things clear.

- This thread is NOT about discrimination of homosexuals.
- This thread is NOT about considering homosexuality as disease.
- This thread is for pure scientific discussion.

Well, let me begin by telling you that I'm a med student and a embriology assistant at my university and I'm not a native english speaker, so you may encounter some grammatical errors in the text, but you'll get the point.
This whole dilemma began two weeks ago, when my brother told my family that he is gay. It was quite a shock, not because of the fact of him being gay but because he doesn't fit the gay man stereotype. He's a big dude, loves sports, bearded, the true definition of what some call "manly man". We accepted him, of course, and I have to say I've never seen him happier.
But after a few days I began to think, was he always gay? Did he decided to be gay? Why now? These questions started lingering in my mind. So I went to talk with my him about it.
He told me that he always has been, for as long as he remembers. Nothing has changed about him, except for his sexuality (for us, not for him haha). So that got me even MORE questions. Why are some gay men that are like extremely feminine? Why are some gay women extremely masculine? Why are gay guys like my brother who don't appear to be gay? Why do some gay people feel like they are traped inside the other genders body and need to get medical treatment (sex change surgery, hormone therapy) and why others don't?And why are there women like that too? Why many species, whose main goal is to survive (actually this is every species main goal, it's literally in our DNA), has certain individuals who are the contrary to this?
So I decided to tackle all these matters from a scientific point of view? What if during the development of the lymbic system (the part of the brain which controles emotions, memory, sexual desire, etc.) something doesn't go as it should?
So after I thought of this I told myself I couldn't be the first one to ask myself these questions. And of course I wasn't in a world with 7 billion people so thanks to the magical power of the internet I managed to get a cool text about the subject. I took some paragraphs which I thought were the most interesting, still I'm leaving the link (please don't take the text as discriminatory, it's merely scientific, it refers to homosexuality as an anomaly in brain developement because seen from a medical point of view it is, still doesn't mean it's moraly wrong).

"..the body and the brain first become sexually differentiated at about the third fetal month. Prior to this age, although genetically male or female, the fetus is physically/sexually-neutral. With the formation of the testes, and the secretion of testicular androgen, target tissues in the spinal cord, brainstem, and cerebrum become activated and transformed into "male" neurons, and form "male" patterns of neural development and neural circuitry, including the pattern of dendritic interconnections between target tissues in the hypothalamus, amygdala, hippocampus, cingulate gyrus, and the bed nucleus of the stria terminals and thus the septal nuclei as well as the amygdala (Bleier et al. 1982; Bubenik & Brown, 1973; Dorner, 1976; Gorski et al. 1978; Nishizuka & Arai, 1981; Rainbow et al. 1982; Raisman & Field, 1971, 1973). It is also well established that the presence (or absence) of testosterone directly effects and determines sexual and cognitive sex differences in mammals including humans (Barnett & Meck, 1990; Beatty, 1992; Collaer & Hines 1995; Dawson et al. 1975; Joseph et al., 1978; Masica et al., 1969; Resnick & Berenbaum 1982).

Presumably, these effects are initially triggered through the differential action of testosterone within target brain areas thus altering neuronal genomic expression (Breedlove 1992; McCarthy 1994 for review). By acting directly on target cell DNA, testosterone (or lack therefore) directly effects neural migration and proliferation vs programmed cell death, and thus cell growth, differentiation, density and myelination (Breedlove 1992; McCarthy 1994; Tobet & Fox 1992). In consequence, a "male" rather than a "female" brain is produced.

The effects of fetal androgens, however, are controlled by a variety of genetic mechanisms which modulate receptor topography and the density of receptor populations which differ during different stages of development and as a function of gender. For example, the genetic sex of the target tissue appears to effect receptor affinity for steroid binding, such as through the secretion of alpha-fetoprotein (Raynaud, Mercier-Bodard & Balieu 1971). These alpha-fetoproteins bind to all circulating estrogens and thus changes their external chemical configuration so that it cannot be recognized by neural receptors (Toran-Allerand 1986). Their chemical configuration is altered and they cannot be taken up by steroid sensitive neurons. Thus these protein act to suppress the influences of these hormones by making them unrecognizable so that they cannot act on the DNA of target neural tissue. Hence, if for any reason there is a failure to produce alpha fetal proteins, females may become masculinized by their own estrogen secretions or the secretions of androgens by the adrenals.

Testosterone however, does not act directly on the genomes of target tissues. Rather, fetal androgens must converted into dihydrotestosterone and into estradiol by an enzyme referred to as aromatase. Aromatase enables fetal androgens to bind to estrogen as well as to testosterone receptors (McCarthy 1994), whereas dihydrotestosterone acts selectively on testosterone receptors. Again, females are protected in this regard by the secretion of alpha-fetoprotein (Raynaud, Mercier-Bodard & Balieu 1971). However, if for any reason these fetal androgens fail to become converted, or if they are prevented from acting on target neural tissue, the female pattern of sexual differentiation will ensue. Although genetically male, the individual may be born with a "homosexual" brain.

Fetal stress may play a significant role in the failure of the male pattern of neural differentiation to unfold, and may well play a significant role in the etiology of homosexuality. Specifically, chronic stress can alter the binding of testosterone, and can prevent testosterone from binding with hypothalamic and amygdala neurons responsible for sexual behavior (Raab & Haedenkamp, 1981). If the fetus is subject to considerable stress, or if "mother" is in an abusive relationship or subject to other profound stress, the secretion of stress-steroids may effect the sexual differentiation and the development of the limbic system and induce the female pattern of neural development. That is, as these stress-steroids, e.g., cortisol and aldosterone, are not true androgens, rather than inducing a male pattern, they may block the reception and binding of fetal testosterone, thereby inducing the female developmental pattern. In fact, the secretion of cortisol and aldosterone--particularly if prolonged--can reduce the secretion of gonadropins (Moberg, 1985), which would also interfere with male sexual behavior and the development of the male pattern of neural development.

As noted, it has been shown that the ventromedial and anterior nuclei of the hypothalamus of male homosexuals demonstrate the female pattern of development (Levay, 1991; Swaab, 1990); sex-specific patterns which may have been induced by stress. If these stress induced steroidal changes also negatively impact the amygdala, affected individuals may not only become homosexual, or sexually and emotionally abnormal."


So, thats all. Hope you guys like it and I wanna see what you think about this.

Anonymous 15/02/07(Sat)04:59 No. 16044 ID: 6a51a1

Racist. Being gay is completely normal.

Anonymous 15/02/09(Mon)17:08 No. 16048 ID: 35ef61

genes are a social constuct

Anonymous 15/02/11(Wed)22:11 No. 16053 ID: b19e9b

I'm a mostly-gay med student myself (and in to neuroscience). The subject is fascinating.

There have been a couple of research papers which show that the endocrine status of the mother during pregnancy affects the physiological and behavioural aspects of the child. These aspects were also found to be different between homo- and heterosexual populations.
So, this makes us question whether the changes in aspects and orientation are caused by the same thing.
Fingers point to prenatal testosterone levels. (Which show an increase when the mother has an atypical endocrine profile).

But there is a ton of variance, and we cannot point to a certain causal link between hormones and orientation.
Just an increased level of prenatal testosterone does not account for all the shades of orientation we see in the Kinsey scale, for example.

And to be rather boring and politically correct, I think "variance" is a better word that "anomaly".

So basically, we just don't know. We have a couple of clues, but the empirical evidence is just not enough.

If you enjoy reading scientific literature, here's a nicely written review on hormones and orientation:


Anonymous 15/05/12(Tue)00:48 No. 16103 ID: b9e6ac

File 143138450912.jpg - (102.83KB , 1000x1000 , 1430216679675.jpg )

Nice introduction

Anonymous 15/05/16(Sat)18:45 No. 16110 ID: 5ab031

ok np

Anonymous 15/05/21(Thu)17:20 No. 16111 ID: 4ceb5a

DNA doesn't lie.
Gay is not normal, although we should not discriminate because of that. It is just a disease just like Down Sindrome.


Anonymous 15/05/21(Thu)17:35 No. 16112 ID: 77222f

being gay is not a disability
...and you are being incredibly rude

Anonymous 15/05/21(Thu)17:53 No. 16113 ID: adac7c

>DNA doesn't lie.
>Gay is not normal
Both of these statements are true but neither is tied to the other.

Every mammal on this planet has shown to be omnisexual at some point in time. Inter-gender, inter-species and even delving into the far fetishes such as necrophilic practices have been demonstrated by every species observed. You say gay is not normal, I agree, neither is being straight.

Everything 'wolfs everything given the chance and denying this instinct denies your own normalcy.

Anonymous 15/05/21(Thu)22:06 No. 16114 ID: 77222f

disregarding all the social implications and connotations behind the word "normal", being gay isn't "normal" as it relates to a minority population.
Same with being blond-haired, or left-handed.

Of course, when used in non-scientific language (such as drawing a parallel with Down "Sindrome"), it is easily read with all the negative connotations included.

Anonymous 15/07/13(Mon)19:18 No. 16173 ID: 1bf875

Mods, a question: why was >>16111 banned?

Anonymous 15/08/14(Fri)11:46 No. 16180 ID: 18b905


If you start adding gender into this argument, it's a whole 'nother clusterfuck.

Consider that a person is typically attracted to a person, and not just a set of genitals; usually they are also attracted to the gender which typically matches those genitals, and also sometimes social mores/standards attached to that gender. For example, most straight men are attracted to female feminine women. That is, cis-gender women that have a female sex and a feminine aspect (dresses/talks like most women do). Most straight men aren't going to be attracted to a female man (that is, a transman that was born female), even though this would still technically be a "heterosexual" couple.

Because of this, I've always disliked the terms hetero- and homosexual, because they are based on the attractor, not the attraction. It's stupid to say that a person's attraction to others changes if they change their own sex/gender. That's illogical; they've changed themselves, not the other person(s). Therefore, I prefer using the terms "androphile" and "gynephile". It avoids this because it doesn't matter what ways an androphile alters his/her sex or gender, he/she will still be attracted to men.

If you look at it this way, this all becomes really quite simple. When you change it from "hetero-/homo-" to "andro-/gyne-", it becomes less of a permanent state, and more of a temporary condition. Now the question of which you are or can be is based on two things:

1) Do you find a particular sex/gender physically attractive enough?

2) Is there nothing impeding you from allowing yourself to have sex with them?

Seeing how nearly everyone can experience a physical attraction (or, for the sexually insecure male: appreciation for) to either sex and gender, 1 is almost a universal yes. This is where the assumption that every person is bisexual comes from. Sure there are outliers, but most people can probably find at least a few examples of people of their non-preferred sex/gender attractive.

Therefore, the reason must be 2; and number 2 is almost entirely sociologically based. In essence, the question usually is: will your peers/family/friends/country accept you having sex with this person?

See, most people won't have sex with a member of their same gender because society won't allow them to. This gets hammered into their brain until they allow themselves to accept the nonsense that being "straight" or "gay" is a permanent state of being, decided before or shortly after birth, and which doesn't change but is only "discovered". Only gay people are allowed to have gay sex, and by the transitive property of sexuality, anyone having gay sex must thus be gay.

Once you realize that this is just silly, and that for thousands of years men have been keeping wives and fathering children, yet having sex with their male friends on the side, do you see my point. Am I saying everyone is bisexual? No. Of course not; that implies a state of being that I've already established does not exist. What I am saying is that, if you strip away all the modern sociological repressions against sex and sexuality, and the illogical desire to label and compartmentalize/categorize people, you realize that everyone most likely has varying degrees of androphilia and gynephilia. Instead of the Kinseyan model of a single sliding scale between homosexuality and heterosexuality; each person has two sliding scales (one each for androphilia and gynephilia) between "no attraction" and "lots of attraction"; this also accounts for some types of asexuality, as people who just have zeroes on both scales — no singular scale can do that.

I don't think there is any reason why the "normal" state is for each person to be more attracted to their opposite sex/gender, either. After all, some primates will have sex with anything purely as social bonding. Humans aren't stupid; they likely have been intelligent enough to realize the connection between sex and reproduction for millions of years. So there is no evolutionary reason for humans to be of a majority attracted to their opposite gender/sex. Unlike lower animals who must have an "urge" or "drive" to mate with the opposite sex in order to perpetuate the species, humans can simply realize that it is something that must be done if they want children. Studies on feral foxes have shown that evolution can happen faster than most people think: in even just a few generations. Might modern humans have evolved beyond requiring such as base drive to mate with the opposite sex? That's just a theory; it's way outside my expertise.

Really, what I'm saying is that OP and a lot of other people are looking at this completely wrong. OP's argument is based on a completely outdated idea that the male sex and masculine gender and XY chromosomes and being attracted to women and having a primarily androgen-influenced brain are all EXACTLY THE SAME THING, and any deviance is "abnormal". Thus, the only way a biological male could be attracted to men is if he had a "female brain". It's laughably nearsighted.

Anonymous 15/08/15(Sat)01:17 No. 16181 ID: 6502a3

>Studies on feral foxes have shown that evolution can happen faster than most people think: in even just a few generations. Might modern humans have evolved beyond requiring such as base drive to mate with the opposite sex? That's just a theory; it's way outside my expertise.
I was on-board with what you were saying until you brought this strawberried nonsense up, although I'm hardly mad, you admit you know 'wolf about it.

With regard to the foxes, they were breeding traits that both of the pair had in common. You can't do the same thing with sexuality.

Two males cannot produce an offspring, neither can two females, you must always have an inter-gender sexual relationship for the creation of offspring unless you genetically engineer the 'wolfing thing. I suppose you could theoretically breed a straight women with a gay man to create a child more inclined for cock or a lesbian with a straight man if you want the child to be clit-happy but those are hardly natural circumstances and the gender of the offspring could throw a spanner in the works.

Anonymous 15/08/16(Sun)23:51 No. 16183 ID: 18b905


Are you implying the homosexuality is hereditary?

Are you fucking stupid?

Anonymous 15/08/17(Mon)00:28 No. 16184 ID: 76c0e8

>Are you implying the homosexuality is hereditary?
Are you implying sexual preference is devoid of a genetic component?

Isn't the implying game fun!

Anonymous 15/12/19(Sat)06:15 No. 16265 ID: b41207

From my little understanding of science (mostly curiosity), don't all mammals and other living beings that have an intelligence to some point, share a basic blueprint for their brains? Could this explain similarities in development and instincts/behavior? OR if the lower intelligence mammals (for example) and their lack of higher reasoning mean that these changes in sexual orientation are maybe an opressed instinct or behavior, or an anomaly in the lower functions in comparison to your brain changing due to the environment around you (society maybe, idk) and that is why we see it across a wide range of species?

Your English is very good, much better than alot of people. I don't understand the the more sciency parts of those articles, but how do you explain bisexuality then?

Anonymous 15/12/19(Sat)06:18 No. 16266 ID: b41207

that is reasonable. this is science and thus (hopefuly) people can look past their definition of words and see that is just a science word.

 Rembrandt 16/01/24(Sun)22:14 No. 16272 ID: af6485

>don't all mammals and other living beings that have an intelligence to some point, share a basic blueprint for their brains?
Yes and no... Essentially, the structures that form in your brain before birth are the result of two things, your genetics, and your prenatal environment. For humans, this is your DNA and your time in the womb. That being said, if you have twins, there will still be some* slight** differences at birth, as every molecule was not in the exact same place for the twins, and due to the butterfly effects of biochemistry, there will be some small differences. If we extrapolate this idea to mammals as a whole, we can see why some species share so many instincts and traits, and why other "closely" related species seem to act so differently. Essentially, the closer 2 species are, the more likely* it is that they will share behaviors.

Now to answer some other questions, (hopefully including a few of OPs)...

As far as we can tell with neuroscience and brainscans, sexuality is determined by a very specific part of the brain. I believe it was at Rutgers University that a study was done on rams which had high rates of homosexuality that they were able to identify which region it is that they believe determines sexuality.

The region in question (ovine Sexuality Dimorphic Nucleus, or oSDN) seems to determine sexuality based on its size, and functions independent of the subject's gender. In other words, when the structure was larger, the subject was attracted to males. It did not matter if the structure was in the brain of a male or female, if it was larger, the subject liked males. Conversely, if it was smaller, they liked females (it may have been the other way around, actually).

Point being, that sexuality is determined by this brain structure, ONLY.

A few implications
>Sexuality is "more or less" independent of the amount of testosterone and epinephrine a subject produces, meaning manly men can be gay (see elaboration below)
>Sexuality is also "more or less" independent of sexual identity. You CAN be a woman trapped in a man's body attracted to women.
>Because the structures in the brain are largely developed by birth time, homosexuality is indeed largely* genetic, though, as previously stated, there is a "nurture" element (also elaborated below)

Now, before I clarify the above two statements, let me clarify bisexuality first, as I caught it while scrolling down and there seem to be many questions regarding this. For starters, bisexuality is indeed real, and can again be tied to the oSDN. While an abnormally large oSDN indicates exclusive sexual appetite for females, and an abnormally small oSDN indicates a sexual appetite exclusively for males, there is obviously blurring on that gradient for any and all in-between sizes of the oSDN.

Now, to elaborate on "more or less". Remember the thing about the connectedness of species? It is the same idea. Technically speaking, there is NOTHING explicitly bonding sexuality and manliness or lackthereof. In other words, there is no law of nature that decrees all gay men (or any, for that matter) must also prance around and have a high pitched voice. HOWEVER, the size of the oSDN is not necessarily incidental. In other words, the same genetic and prenatal anomalies that cause one to be heterosexual or homosexual also probably affect behavior, and thus, there is probably a strong link between the behavior and the sexuality.

The same idea applies to gender identity vs sexuality. The genetic components that cause gender identification-identity mismatch (I just coined that, yw) may incline the subject in question to be more "heterosexual" (in quotes, because the idea can be confusing for transgender people). That is to say, they are heterosexual with respect to the gender they identify with.

 Rembrandt 16/01/24(Sun)22:32 No. 16273 ID: af6485

Now, I mentioned the word "nurture" above. The reason this was in quotes was because "nurture" is not really the correct word here. In short, your genes are merely blueprints from which your cells build proteins. They can technically "ignore" portions of the blueprint (ignore was quoted to emphasize that cells dont have free will). In essence, if a gene is methylated*, there is an additional molecule attached to the DNA strand that essentially says "Don't read from me". This can happen from a number of ways, including but not limited to childhood trauma, but is MOST prevalent (in the case of sexuality) in the womb. In other words, no one from your family talked your brother into being gay. BUT since this is technically* an environmental factor, I am forced to use the word "nurture" since everything has to be of the form nature vs nurture nowadays.

Now, to tie everything together...

It is important to remember the importance of culture... while culture does not necessarily* "make" someone gay, or necessarily* "make" them "manly", it has a clear affect on the way we think and act. Consider the stigma surrounding homosexuality, not just within the United States, but especially* elsewhere. It would behoove anyone who is gay or bicurious to act extra "manly". Over time, these "pretend" traits rub off on us (see: Irving Goffman, and the dramaturgical self for more info on that). In other words, society and culture may have made your brother "manly".

Likewise, consider the psychology of sadomasochism. Masochism is typically tied to feelings of guilt, whereas sadism is tied to feelings of resentment. Guilt and resentment are not innately a part of the human brain, they are acquired. Likewise, if I masturbate repetitively to the same type of pornography, day-in, day-out, eventually I will get bored. I will start to deviate. Milfs no longer tickle my proverbial fancy, and now I need asians, or bbw, or etc. Technically speaking, someone who may not ever want to have sex with men, or who may never want a relationship with men, may indeed watch some gay porn. Technically speaking they aren't "bisexual" in a strict sense, and there is no permanence to them wanting gay porn (they can go back at any time). Whether you choose to stick with the biological definition of sexuality (this person would not be considered bisexual) or you decide that "if they watch porn for both sexualities, they are bi" is sort of a decision that you will personally have to make.

All that being said, it doesnt sound like your brother is "temporary gay".

Last but not least, culture affects -and is affected by -culture. Consider the following: Your parents ask you to take out the trash. Now consider two scenarios...
>You remember to take out the trash, and do so.
>You forget.
Which one do you think your parents will remember more? As sad as it may seem, the Architect in "The Matrix: Reloaded" has a point, human beings define their existence in terms of misery.

Consider another scenario after the previous.
>You remembered to take out the trash last time, you do it on your own as a surprise this time
>You forgot last time, your parents havent asked you since
There is a good bet that your parents will not notice the additional help this time, and if they do, they will forget in a day or two. Conversely, they probably still remember the time you forgot.

 Rembrandt 16/01/24(Sun)22:43 No. 16274 ID: af6485

Thus, we have to ask ourselves, "Are gay men effeminate because they are effeminate, or are they effeminate because we notice and remember every single case of gay men being effeminate?"

The answer is probably some of both. "Stereotypes exist for a reason" is an incredibly true statement, if for no other reason than "someone is propagandizing a stereotype" (see: WWII & the Holocaust).

All that being said, the short answer to a lot of the questions people ask about sexuality is: "Its complicated" because it is. To rapidfire answer some faqs, though:

>Is being gay genetic or learned
Almost entirely genetic, bisexuality can somewhat be "learned"
>Can you be a masculine gay man or an effeminate gay woman?
>Can you be a gay transexual?
>Is being transexual genetic or learned
As with homosexuality, it is roughly 100% genetic
>Is there a scientific correlation between homosexuality and masculinity/effeminacy for a specific gender?
Not yet, but this probably has more to do with the impracticality of carrying out such a study. A study could be carried out that says "Yes, a strong correlation" which is entirely botched and less than scientific. The short answer is that we just don't know yet BUT it should be noted that in one study, groups of homosexuals and heterosexuals were dressed in the same clothes, had their pictures taken with a blank expression, and shown to a test group. The test group were able to determine if the person was gay about 80% of the time accurately. Not a grand statement, just food for thought.

Also, as had been noted, OP, your english is far better than most of my friends', and I appreciate the research you took the time to do on your own.

Hope this helped clear some things up for someone

 Rembrandt 16/01/24(Sun)22:52 No. 16275 ID: af6485

In my second post:
>culture affects, and is affect by culture
was supposed to read
>culture affects, and is affected by perception

It was also greentexted there.

Anonymous 16/01/27(Wed)06:48 No. 16276 ID: b41207

You make some very good points. I do not have a great understanding of anatomy or biology as a whole, but I have always believed that the reasons behind a person's personality was genetic (to a point) or atleast heavily affected by it. As you said, society also plays a role in the perception or movement on these actions relating to personality. If you are conditioned by the people and ideals around you to be something else, then you most likely are going to become that. Also pertaining to the environment around someone, and how it effects them: if a gay man for instance was only in contact or even only knew of women (besides himself), then this man would have little idea that he was gay. Perhaps he would not feel whole, or a little voice in the back of his head wanting something different, but the idea of wanting someone different would be little existent. I ocassionaly see posts on other imageboards following the idea "the internet made me gay". Perhaps these people always considered themselves straight (as heterosexual is the norm) and never saw gay porn because the mentality " I'm straight not gay, I don't watch gay porn", and once being exposed, they realised these suppresed or blinded tendencies.

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