Over time I came to realize that people use at least three different definitions of sexual orientation. I believe all have their place, but it's important to note the differences and sometimes disambiguate, otherwise you can get in a situation where two people really agree with each other but get in an argument because they use conflicting definitions without realizing.
I'm calling this biological for lack of a better term. It seems to be an aspect of a person that is either inborn, or develops very early, and is involuntary.
Most homosexuals will note, for instance, that as they reached adolescence they already started to note their homosexuality; that they simply never found the other sex attractive, and found the same sex attractive instead. This is behind the "born this way" narrative, and it's somewhat supported by science as far as I understand.
Since this is about involuntary attraction, it's noteworthy that it can be "error prone" so to speak. The brain probably pays most attention to secondary sex characteristics to decide whether it finds a body attractive. For instance, heterosexual men frequently find "shemale" pornography arousing, even though they know, consciously, that what they see is a male person. The conscious knowledge of the person's maleness does not erase their inner drive towards finding the person's secondary sex characteristics attractive (so long as there is not a strong homophobic reaction masking it), so you end up with a heterosexual man finding another person they know to be male attractive regardless, because what they see is nevertheless a female-seeming body.
(However, it's also important to note that a lot of what seems to be a natural sexual attraction to "feminine" or "masculine" attributes, might in fact be learned fetishization, especially in males. All too often, men will be aroused by cultural markers of femininity such as makeup, lingerie, stockings, high heels, and so on. These have, obviously, nothing to do with female sex characteristics.)
This is a definition of sexual orientation that is imposed on a person, possibly by themselves but often by others, based on their observed sexual behavior, and the attribution of homosexuality or heterosexuality to the particular behaviors they exhibit.
For instance, a man might be heterosexual biologically, but nevertheless have sexual activity with other males who he finds attractive due to their bodies appearing female-like (natural) or stereotypically feminine (fetish). This man might be attributed bisexuality since factually speaking he has sexual encounters both with men and women.
A very common misapplication of the idea of behavioral sexual orientation is men calling other men gay for having had any sexual contact with another man. They impose heteronormativity and refuse to acknowledge bisexuality. In addition, the man in question might even be biologically heterosexual. The phenomenon of viral "trap" images on the Internet, where an attractive female-looking person is revealed to be transsexual i.e. male, plays on this phenomenon; the male audience is intended to feel shock and shame at their attraction for the person who came out to be male, proving them "gay".
For many if not most people, their sexual orientation is an intentional part of their personal identity. They will consciously limit their sexual behavior so as to conform to a certain behavioral sexual orientation, possibly even going against their biological sexual orientation in the process.
The most common occurrence of this is probably in homophobic men, who work hard never to come in any sort of sexual contact with another man, lest they become non-heterosexual, or "gay" as they would call it (actually just behaviorally bisexual). Even a biologically gay man might force himself to live heterosexually because of homophobia.
Another variation of this is political lesbians, who as a political statement refuse sexual contact with men, regardless of what their biological sexual orientation is.
A person might have no intentional sexual orientation, meaning they don't care about limiting their behavior to anything. Such a person might behaviorally end up of any sexual orientation, and might claim a number of different orientations when asked. For instance, maybe they would be bisexual but happened to never encountered a same-sex partner they found attractive so far, and when asked they just call themselves heterosexual. Conversely, maybe they call themselves bisexual because they can imagine finding someone of the same sex attractive. Or maybe they thought more deeply about it and decided to call themselves pansexual or omnisexual. (Although those can be intentional sexual orientations as well.)
In light of this taxonomy, I'd like to make a few political points.
While it's interesting scientifically, and perhaps useful for some other reasons, to acknowledge biological sexual orientation, I believe it's dangerous to rest one's LGB activism solely on that base. It's important for society to understand that people should be free to make whatever kind of love they want to make regardless of what's biologically explicable or "natural". Some recent study even found that teaching someone the biological base of homosexuality does jack shit to challenge their bigotry. So much for that.
Transgender politics are haywire, and the interplay of transgender issues with sexual orientation is no exception. While I acknowledge that biological heterosexuality or homosexuality are not necessarily a barrier to finding someone of the same sex or opposite sex attractive, when the person passes well as a member of the sex they imitate, it's important also to pay respect to political identities of some sexual orientations. In particular, I find it ignorant at best, and pretty vile in some pathological cases, when transgender activists criticize lesbians for categorically refusing relationships with male-to-female transsexuals.
That's all for today.
⚢ ⚣ ⚤