Today, I had the opportunity of attending a symposium on the biological research being done with the hopes of understanding how sexual orientation is determined in humans. What makes someone gay or straight? The first presenter, Dr. Mike Bailey looked at what it means to have a sexual orientation. Is it the type of person you're attracted to? The person you like to have sex with? The person you fantasize about? The person that arouses you? These are very different definitions of the term "sexual orientation." The research presented suggested that in men, sexual orientation is determined by sexual arousal patterns--the type of people that arouse you are the ones that define your sexual orientation--not the ones you have sex with or fantasize about or think you like (although these categories do overlap). For women however, no such pattern existed--there was equal genital arousal for both the preferred sex and the less preferred sex. Does this mean that all women are bisexual? Does this mean that women do not have sexual orientation, in the way it is defined for men? In defending his definitions, Dr. Bailey stated he did not like the idea of two different terms for sexual orientation for men and women--the term is already ambiguous enough. However, the way it is determined now does not explain both male and female arousal patterns.
The second presentation was an explanation of what causes someone to be gay. Dr. Ray Blanchard presented on his maternal immune hypothesis and the fraternal birth order. This hypothesis suggests that the more older brothers a man has, the more likely that he will be gay. Why? He hypothesizes that male fetuses do something to the maternal immune system--that she produces antibodies to an "anti-male" antigen that later affects future male fetuses, just like any virus reinfecting a body. The more older brothers, the more likely that a man will be gay, regardless of whether he lives with those brothers or not. This immunological hypothesis only applies to older brothers affecting younger brothers--sisters have no role in the matter, theoretically since they have the same types of chromosomes and proteins that a mother would, both being female. Yet this hypothesis is just a hypothesis. And while it has considerable evidence supporting it, there is no definitive conclusion as to why this happens to younger brothers. Could there be something to determine "gayness" for a firstborn homosexual similar to the maternal immune hypothesis. The commenter for this speaker suggested using DNA sequencing before and after the birth of a male child to see what changes in the mother--hoping to provide a definitive conclusion as to what causes this phenomenon.
These topics are very interesting to me, as I am taking an anthropology course on the evolution of human sexuality. They provide explanations for why and how certain phenomena occur. They do not negate other causes or interpretations, such as genetics, hormones or environmental factors, yet they provide a supplementary explanation with evidential support. It was a very worthwhile symposium, and the class (ANTH 216) is very interesting!
The second presentation was an explanation of what causes someone to be gay. Dr. Ray Blanchard presented on his maternal immune hypothesis and the fraternal birth order. This hypothesis suggests that the more older brothers a man has, the more likely that he will be gay. Why? He hypothesizes that male fetuses do something to the maternal immune system--that she produces antibodies to an "anti-male" antigen that later affects future male fetuses, just like any virus reinfecting a body. The more older brothers, the more likely that a man will be gay, regardless of whether he lives with those brothers or not. This immunological hypothesis only applies to older brothers affecting younger brothers--sisters have no role in the matter, theoretically since they have the same types of chromosomes and proteins that a mother would, both being female. Yet this hypothesis is just a hypothesis. And while it has considerable evidence supporting it, there is no definitive conclusion as to why this happens to younger brothers. Could there be something to determine "gayness" for a firstborn homosexual similar to the maternal immune hypothesis. The commenter for this speaker suggested using DNA sequencing before and after the birth of a male child to see what changes in the mother--hoping to provide a definitive conclusion as to what causes this phenomenon.
These topics are very interesting to me, as I am taking an anthropology course on the evolution of human sexuality. They provide explanations for why and how certain phenomena occur. They do not negate other causes or interpretations, such as genetics, hormones or environmental factors, yet they provide a supplementary explanation with evidential support. It was a very worthwhile symposium, and the class (ANTH 216) is very interesting!
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