The first sexual orientation label I ever gave myself, at age 14, was bi. I didn't have to question my sexuality to get to that--it was just obvious and simple and easy, or at least that's how I remember it. I reacted to boys and dreamed about girls. Of course, social pressures and teen angst step in, and so for a few years I try to cut my sexuality into easily-understandable pieces, question whether I'm straight or lesbian or asexual, beat myself up for never having kissed anyone, much less had sex with males and females to "prove" my orientation, etc.
At the same time, I'm angsting about gender. I'm railing against a lot of the female gender stereotypes/roles people perceive and pressure me to be in. I've been raised with a lot of misogyny, and maybe I invented some of my own out of resentment of the gender I'm imprisoned in. I struggle to accept feminism despite cultural indoctrination to reject it, struggle because I love women and girls and I can't not want to champion them, struggle because I find myself expressing my lust in predatorial thoughts that make me all the more aware that women can be victims. I become anti-gender, envisioning an ideal society in which people act according to their proclivities without necessity of categorizing.
Then my best friend comes out as FTM. He looks better as a guy, and I'm miffed that he didn't come out earlier so he'd be comfortable responding to my flirtations. I move away, so that comes to nothing, but I've embraced the androgyne gender identity. I obsess over gender for a while, before realizing that there's nothing that basically different about me (well, part of me knew this all along--it just takes time to assimilate things into a dynamic identity such as we all possess) except what I believe:
People are people. The "scientific" studies that reveal cognitive sex differences usually only report small differences in the statistical means of overlapping curves, many of which, like mathematical ability, may be a product of cultural context or study bias.
Sex and gender are different. Gender is a set of arbitrary rules and ingrained interpretations of data that just doesn't reflect reality for individuals. In most contexts, ANYONE (and especially me ^_^) might just as well be male as female. The only times these matter have to do with sex (the act), reproduction, and related organs. Of course, societies make sex/gender matter in a ton of other contexts in defiance of common sense, and that's what makes me a cheerful feminist. (If you don't understand the above, here's an example: We have different sentences for if a male or a female goes to the store, takes care of the kids, etc, depending upon the gender or sex we assign this person. "He took the kids to the store," vs, "She took the kids to the store." These sentences summon different mental images, but is there really a difference in the act? Do you really get meaningful information about a person just from knowing their gender--have you never been surprised by someone's appearance because they deviate from your generic "mother" figure, for example? I think it's harmful that such genderless activities are genderized by our use of pronouns and gender-specific naming conventions because it facilitates the creation and perpetuation of gender stereotypes. Where I grew up, any male who showed interest in literature or creative writing got slammed with homophobic suspicions of being gay. Obviously, this isn't good for my home region's cultural, intellectual, or emotional development.)
Sex is almost as arbitrary as gender. There are exceptions to the karyotype (XX = female, XY = male) and genital (penis = male, vagina = female) rules, but, more importantly, every human being experiences unique physical and emotional development with regards to sex. No one hits puberty at the same time, not all men have facial hair, every woman's labia resemble a different breed of flower. Not everyone with a uterus can medically bear children, and not everyone with a penis has a libido. So many people, especially preteens and teenagers but also a regrettably large number of adults in our society, feel insecure or hold themselves to unrealistic demands to match the label they've been given.
Sexuality means more than we give it credit for. It's the longing to touch another's skin, to share a deep emotional connection, to hook another personality to your own, as much as it is about more clearly sexual pleasure, and there's a lot of that. It includes ************ and partnered sex as well as grooming and self-presentation, how one fits into a larger social environment as well as how one relates to oneself and to a close partner. You can be sensual or sexual without stimulating sex organs at all, and on the flip side you can be sexual just by stimulating those organs, without being aroused by someone else's body or experiencing an emotional connection, and you can experience an infinite amount of other combinations, and you just about will--something's different every time.
Sexual/romantic orientation also has more to it than gender/sex. It's about how different people may or may not fulfill any of the above sexual desires, and a lot of that seems random to us or can't be controlled. Usually orientation is interpreted as excluding a segment of the population from one's dating pool--if you're homosexual, you're not going to be interested in people of the opposite sex. If heterosexual, not the same sex. If bisexual, anything goes, but if asexual, don't even look. And I think some people really do feel a strong enough orientation that they couldn't have a fulfilling relationship with one of the excluded people, but the problem is that a lot MORE people are excluded in most people's orientation than are indicated by the homosexual/heterosexual labels. Some people just don't click. Others are excluded because of age, lifestyle, or a million other factors. Are the hetero/homo labels really so useful when we already have to have fine-tuned sensors to hone in on the one case of mutual attraction out of a thousand or more no's? (Of course, sociopolitically the LGBT labels have been vital to earning recognition and fighting prejudice, and it's certainly useful for the sexual minorities to create a community to increase their/our likelihood of meeting a "yes".)
I'm pansexual because of who I have wanted and who I have loved emotionally. I don't know what physical sexual features (which certainly have more than two types--I was checking out a scrawny guy with beautiful, delicate hands and scraggly, long hair and facial hair on a narrow, acne-ridden face the other day) or gender/personality traits will attract me next. The only thing I can expect is that my attractions will continue to be diverse, and that I will not exclude anyone solely because they are male, female, intersexed, transgender, androgyne, butch, femme, etc.