Theories aren't facts unlike many people who treat them as so. But theories with more evidence or strong evidence are "better" than theories without evidence or with less evidence.
I'll tell you why "I don't believe" people are born right or left handed. I've been playing guitar now for over a decade right handed, seeing as my right hand is my dominant hand. I then once tried flipping it over to play it like Jimmy Hendrix did. As I was teaching myself I realized something that is contradictory to the THEORY that people are "born" right or left handed. My left hand's fingers were better at finger-picking than my right hand's fingers, and my right hand's fingers were way slower and less coordinated playing on the frets than my left hand. And my left wrist is slower at picking than my right wrist. But I write better with my right hand. This didn't make sense until I changed my belief system to believe people aren't born that way... now it makes more sense. I now believe because I've been using those specific muscles more and longer, they are better than the ones I haven't used as much.
More "evidence" that more solidified my belief in this Not-born theory is this: I know a guy who was right-handed, but lost his right hand in a work accident. He was in my English class and had to take a TIMED writing exam with his left hand - his non-dominant hand. And he succeeded and is now just as good with his left hand as he was with his right hand.
Also I have asked several left-handed and ambidextrous people if they agree with this theory and they do and usually have some first-hand experience that they tell me about to more support this theory.
That is why "I don't believe" people are born right or left handed.
Some kids have it in them that they will go bald by age 40, doesn't mean they have to start losing hair when they're 5.
I agree with you about the balding, belief is not the root of all physical states and changes, but belief IS the root of all actions. Things like kissing, touching, and further are intimate actions, therefore intimate actions are rooted in belief, therefore sexuality is caused by belief alone. If something else has just changed your belief on something, then you have just been brainwashed(by my definition) which is not always a bad thing. All sexuality is either by choice or by brainwashing. Also, brainwashing(by my definition) is extremely difficult to overcome once you realize what it is. So having a healthy cynicism and assuming people will not choose the difficult path to overcome it, I realize it's better to assume brainwashing isn't a choice. Being straight is no exception, neither is believing in a religion, or the way a person is raised, these are all brainwashing. This is one big reason WHY we SHOULD have freedom of religion, freedom of sexual orientation, freedom of attraction, freedom of marriage, and probably more.
seriously? i can tell when a man is attractive, but he's not attractive to me. in high school i started dating a boy i could see was cute, but when i kissed him i literally felt sick and trapped inside. i have never once felt that when kissing a woman. it wasn't about good or bad experiences. "joe" was a nice, charming fun young man. we're still friends to this day. i just have no sexual attraction to men. it's not there. women do it for me.
I appreciate that you took the time to share this first-hand information. I believe arguments like you gave are probably the best since it is self-evident to anyone who reads it.
As I read your story, the first thing that popped into my head was beer. As an analogy. I remember the first time I drank beer it tasted awful, made my stomach uncomfortably warm, and it made me kind of jittery. I've never felt that when I drank water or juice. I still to this day won't even take a sip of beer. Water and juice does it for me. But what amazes me is the number of people who drink a lot of beer. Surely beer gives good experiences if so many people drink it a lot, otherwise why would they drink it if it never gave them a good experience? Maybe everyone who drank beer(or in your case, everyone who kissed a guy for the first time) had a bad experience the first time, but didn't let them stop the next time, or the next, or the next. Like an acquired taste. I had the same exact experience you did with kissing a guy and kissing a girl, kissing the girl felt so right, and kissing the guy was kinda scary and uncomfortable.... the first few times. And then my negative emotional response became desensitized over time and it turned into positive emotions through enough effort and a change in my belief system. I bet it was the same(or at least VERY similar) with people who now love drinking lots of beer.