I am a bisexual woman who is securely comfortable in her gender identity. While I think "woman" should encompass a far, far greater scope of ideas, beliefs and actions than it stereotypically does, it's still a label I am comfortable accepting, since we live in a world of labels. That is how we function, giving names to one another. I don't always like it, but I can live with it.
I consider sexual orientation and gender identity separate things. I also think both have their own spectrum, and that while many people are comfortable at one end or the other there are plenty of people who fall somewhere in the middle, and some who like to move up and down the scale. Me, for example, am mostly oriented straight right now because I'm having sex with men right now. Either that will change, or it won't. But I stick to the bisexual label because women in general still turn me on.
Likewise, some people don't fit in neat gender categories, either because they are physically intersexed, or because they have the genitals of one sex but their brain is wired to be the other. They find various ways to accomodate these differences, but eventually they have to choose "woman" or "man". They can and should be able to stretch their particular chosen category to suit their personalities and tastes (as much as I hate these terms - an "effeminate" man or a "butch" woman), but they still have to pick one. We are wired to look at each other that way, as women and men, as Mommies and Daddies or Aunts and Uncles. So, one chooses, as difficult as it can be, and tries to live with it as best they can.
So you have to choose "man who likes women" "man who likes men" "man who likes women but has no problem with doing a guy now and then" and so on and so forth.
This choice is not easy for many, and for some it can change at any time...maybe a woman who has always been straight suddenly finds herself in love with another woman. When experimenting, there should be extra care taken, both of yourself and of the people who consent to be your partners in your exploration, because communities that suffer the slings and blows that the GLTB community has would have to be cautious. There could be more at stake than broken hearts alone. This might not be as true now as it was in the past, but ask the
lady in Vermont who has been fighting for years to see her adopted daughter about what could be at stake.
My point is that neither identity or orientation are jokes, to be played with and tossed aside when it's "time to grow up". Sometimes I wish we lived in a culture with more fluidity in these matters, but we don't. The label you take on in both areas permeates every aspect of your being and your interaction with others. Some have paid a big price for taking on a label that others didn't approve of. It's not a game.
If someone is going to transition from one gender to another, then they should approach it seriously and cautiously. But until the process is well underway, it is possible for others meeting that person to mess up, because they are seeing through the gender lens (it's hard to ignore a pair of big boobs). So understanding and patience is needed on both sides. Consistency is also key. Do it, or don't, but don't get mad at the rest of the world for not "getting it" when you still have a beard and a boy's name. That seems to me to be entirely disrespectful of the commitment a transgendered person has made. This isn't to say you can't dress in drag, but when you're being a girl, be a girl, when you're being a guy, be a guy. Don't deliberately confuse people and don't fuck around with it because that's rude to them and rude to the people who live with their choice of label no matter how tough it gets.
This is different from acting. I'm talking about RL situations, though in general terms. And I acknowledge that sometimes being in drag is just acting, but for some it is more than that.
This has been inspired partly by Ursula K LeGuin's Left Hand of Darkness novel that I just read, though my thoughts went way off the topic of that book.