Thursday, May 24, 2007

Interesting Psychology Read

Was reading thru psychology text (really did it out of interest as well) for my quiz and i came upon an interesting finding. Ok i was at this chapter on Motivation and Emotion. My class is focusing on SEX which is viewed as a non-regulatory drive whereby many studies were conducted on it (it was extensively experimented by my classmates as well =p, judging from their eagerness). Was reading thru some of the scientific stuff and parts of the brain associated to it. The most interesting theory that came across my eyes is this one: Fraternal Birth Order Effect on Male Homosexuality.

This effect describes that the percentage for a male to be gay is heightened as his birth order increases. Which means if a male has more elder brothers, his chances of being gay is increased. According to a study, on average a couple's first son has 2.0% chance of being gay and that this percentage increases to 2.6% for the second son and then 3.4%, 4.6% and 6.0% for the third, fourth and fifth son respectively. The number of elder sisters a male has plays no role in this effect.

The best part is the scientific explanation which swept me away. The most prominent current hypothesis is that the effect results from a change in the prenatal environment that is induced by the previously borned sons. Genes on the Y chromosome of a male fetus produce certain proteins that may help androgens to masculinize regions of the fetus's brain. These proteins are foreign to the mothers' body; so if they get into her bloodstream, they are likely to induce an immune response from her. With successive sons, the immune reaction could generate sufficient supply of antibodies that hinder the proper development of masculinity in fetus's brain!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I think about some of my uncles and it seemed to be true.. his behaviour is rather effeminate. My friend (due to privacy reasons i better dont say the name) also added to this credibility.. of course some are married but.. hmm.. Do you have highly birth-ordered uncles?

Oh yah.. it is also highly believed that a particular region of the male brain needs to be developed thru presence of androgen/testosterone in order to exhibit male sexual behaviour. We all know that testosterone is also responsible for fetus development of the penis from gonad (male baby), otherwise the fetus will develop a vagina (female baby) [There are some cases where improper development of gonad results in Intersex] However there are actually two independent systems that govern the release of testosterone to the brain and to the body.. this explains transexuality. A male transexual's (male thinking he is a female trapped in a male body) brain was actually cut (after he is dead of course) and was found to have that particular region to be the same size as a normal heterosexual female. So it is genetic?

blabbered by Jinzhan at 6:36 PM |

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