Comments on: Multiple factors involved in sexual orientation: New study

By: carole

carole — Thu, 03 Sep 2009 16:34:53 +0000

@Evan,

The amygdala differences are more interesting, but, again, we have to see the study.

Here’s an interesting article–for what it’s worth, once again, activity in the amygdala is the focal point.
http://www.livescience.com/culture/090903-seizure-switch.html

By: RandomEffect

RandomEffect — Thu, 04 Dec 2008 01:17:48 +0000

One thing I’ve thought of that I bet nobody else has mentioned is that part of the chance of your sexual orientation may be what we think of as randomness. Of course nothing is really random if you look at it very closely. I’m talking about the Butterfly Effect. This will probably confuse a lot of people, but bare with me. The Butterfly Effect comes from the idea that if a butterfly flaps its wings it can cause a tornado on the other side of the world. Basically all the matter and energy in the world is physically connected somehow so a physical or chemical reaction that happens anywhere in the world will have some influence on all the other ones that happen in the future. If one was different it might in some cases change the whole outcome, but usually you’d probably have to many be different, maybe even millions for it to affect the outcome.
The human body is basically matter and energy interacting together to somehow produce consciousness and everything that goes with it (desires, feelings, etc.), so there’s no reason why another chemical reaction, especially one that’s in your body wouldn’t have any impact on future ones. What ever chemistry produces attraction towards someone is the outcome of a very long, chemical equation containing all the chemicals that have ever interacted with your brain and all the chemicals that interacted with those chemicals and so on and so forth. So that would mean that had millions of seemingly unrelated factors been different (you ran one day instead of walking/vice versa, you eat a little more/less, how long you slept, what you watched on tv, even just stepping down your foot one inch forward/backward (since every action essentially sends out chemical signals)) your sexual orientation could be different. And it wouldn’t even be consistent like for example if everytime you overslept that increased your chances of being heterosexual. Instead it would be like you oversleep and that changes a variable in the chemical equation and how that affects your sexual orientation would depend on how it interacts with all the other variables so sometimes it could make you more likely to be straight, sometimes gay, and sometimes bi.
Final note, what do you think caused you to like the foods you like or the smells you like? You probably just think you “just do”. Of course something determines that 2, millions of factors including a few ones where the relation can be easily seen and millions and even billions that would seem to have no logical reason to affect the outcome but still do through the Butterfly Effect.

By: Evan

Evan — Fri, 04 Jul 2008 16:30:13 +0000

Drowssap,
Anxious personality is based on stable brain patterns that are probably the result of genetics, hormones and how these two factors conspired to influence someone to have certain behavioural tendencies, like avoiding aggressive games or confrontational situations. Actually a recent study shows that trait is manifested all the time as a form of vigilence even in quiet environments. Being that aggresiveness and competitiveness are male-typical characteristics, these anxious kids probably perceived their same-sex peers in a manner that is typical for the opposite sex (they could have been ‘kitchen boys’ or ‘sissies’). This might explain the same amygdala patterns in male homosexuals and female heterosexuals. They used their brain in the same way in relation to the male sex, but the causes might not necessarily be the same. It could be that some genetic factors predispose some men to greater anxiety which is atypical for their gender. This factor alone cannot cause atypical attractions, but it probably contributes to the final outcome. Still, the amygdala is involved in many cascading effects throughout the entire body. There are unexpected relations between these effects, like:
–greater anxiety which can also increase pain sensation (hyperalgesia),
–greater anxiety can increase physiological arousal,
–greater amygdala activation can cause greater visceral sensitivity along the brain-gut axis – especially in the lower gastrointestinal tract (intestines and anus).
But the amygdala does not play a role in these reactions by itself, it’s integrated in a number of specialised networks. For instance, a probable network for sexual behaviours includes the amygdala that makes the emotional assessment of stimuli, the ventromedial nucleus of the hypothalamus (which triggers lordosis in the females and mounting in the males) and the periaqueductal gray (involved modulation of pain, defensive behaviour, lordosis). If these areas are somehow less masculinised or too effeminised they might trigger body reactions that are atypical for an individual’s sex status.
That can happen in many ways. A combination of genetically caused androgen receptors problems and how they interact with a certain level of hormonal exposure. Or it could only make a difference in a few specialised areas, regardless of the overal level of hormonal exposure.
But as I said there must be another brain area that manages aggressiveness and allows a greater degree of stimuli input in the stress system, which overwhelms it. This is known as a sensory gating problem and has caused many disorders, which might also account for straight women’s and gay men’s greater vulnerability to stress and mood problems.
So, differences in aggressiveness and sensitivity are probably correlated with gender feelings. But there are too many black boxes in the human system to be able to tell, like scientists who work on animal models, that there could be a switch, upstream the brain circuitry that governs gender-typical dimensions, that can awake different gender potentialities in the same brain. That might be a whole different issue than what scienstists in the field of sexual orientation study right now. Aggressiveness could be a by-product of a region that switches more or less the gender status of an organism. But then, again, why are there no same-sex oriented mice in the wild but there are same-sex oriented monkeys? Maybe humans and higher primates have lost that switch (the vomeronasal organ) and they only rely on the former by-products of gender-typical hormonisation and genetic sex status.

By: Drowssap

Drowssap — Tue, 01 Jul 2008 15:38:49 +0000

Evan

Well, greater anxiety or vigilance might have come handy in dangerous environments, it might be that sensitive men might have had to compensate their lower aggressiveness by greater inventivity.

I think that’s the big question. Do traits like greater sensitivity lead to homosexuality or are these traits biproducts of whatever triggers homosexuality?
My personal guess is that these traits are biproducts of the SSA trigger. The recent Swedish study that found greater amounts of “feminine” wiring in gay men concluded that this wasn’t the result of natural genetics. Something out of the ordinary was responsible. It could have been hormones but even in this case why would the hormones have spiked or washed out or whatever during development?

By: Evan

Evan — Tue, 01 Jul 2008 06:42:25 +0000

Drowssap,
Humans have some peculiarities compared to other species. A teenage phase is one very important for brain development. There is no need to have a perfect bell curve of sexual orientation. The actual bell curve would be that of hormonal factors, like aggresiveness. Throw in some genetic factors for amygdala patterns that predispose some males to anxiety (there is a whole spectrum) and you’ve got a composite bell curve of predispositions slightly amplified in sensitive men (anxiety, vigilance, avoidance). That is why there was a need for culturally enforced gender segregation: to fill the void of a gender switch advantage that was lost. So the bell curve of predispositions had to be adjusted by cultural nudging. You won’t see that in mice, because there is no same-sex oriented mouse in the wild. If they had no gender switch, they would have gone extinct.
What evolutionary advantage gender variance may have had for humans? Well, greater anxiety or vigilance might have come handy in dangerous environments, it might be that sensitive men might have had to compensate their lower aggressiveness by greater inventivity. They could have become healers, shamans or very knowledgeable tribe members that did not need to reproduce as much as the other men. The only chance for a ‘gay’ set of genes to survive would be to have a normal distribution in the population, that maintained a marginal strong effect and a greater weak effect in the rest of the population. So each generation would have a statistical “tail”, but the greater populational effect would be preserved by differing mating strategies: masculine men would pick the best females and less masculine men would settle for females who have a harder time finding mates among the more aggressive males (because of being deterred by their aggressiveness).
Another possibility is that the genetic effects would be the only ones that have been actually passed on, while the hormonal effects might be due to many environmental factors that could be variable at different points in time. Compound factors might be variable across evolutionary ages. I dunno, just a possibility. 🙂