Alfred Kinsey, who created the Kinsey Scale, a scale which people use to pinpoint where they fit along a spectrum of sexual orientations, made a few mistakes in its implementation.
The Kinsey Scale categorizes people on a scale from 0 to 6:
0. Exclusively heterosexual.
1. Predominantly heterosexual, only incidentally homosexual.
2. Predominantly heterosexual, but more than incidentally homosexual.
3. Equally heterosexual and homosexual.
4. Predominantly homosexual, but more than incidentally heterosexual.
5. Predominantly homosexual, only incidentally heterosexual.
6. Exclusively homosexual.
The failing in Kinsey's scale was that it was not based on attraction, but was instead based on experiences. So, a person who viewed themselves as 100% heterosexual, but who had, say, that one ubiquitous experimental drunken moment with someone of the same sex, back in their college days, well, now that person would be a One on the scale. Forever branded a One, due to one incident. That hardly seems fair, nor accurate. What if they were abused as a child by someone of the same sex? That could also change their score, regardless of their actual orientation.
Another flaw in this was that it didn't take into account asexuals. Later on, a scoring of X was added, to represent those who were asexual. But, again, since it's based on experiences, rather than attraction, and since many asexuals have had sex, for utilitarian reasons, typically, they would be scored as anything other than what their actual orientation is.
The biggest problem, though, as I see it, is that we can't really be scored on one simple scale. Numerous things need to be taken into account when looking at orientation. As a society we're now starting to become more aware that there are those of us who don't really fit into a gender binary of male or female. There are some who are transgender; who were born male, and are becoming female, or vice versa. But there are also those who were born intersex. Additionally, there are some people who feel that they are both male and female. They are bigender. Some feel like they are neither gender, not really belonging to either males or females. When talking about gender, we basically ignore the genitalia. For genitalia, we talk about sex. And that's another matter... but it's so closely tied to gender, that you can't really completely separate the two. They're interconnected... somewhat.
So, we would need one scale to represent gender. On one end you'd have to have Male, and Female at the other end (or, perhaps, Masculine and Feminine). In the middle would be Bigender. Outside of this scale would be Agender. Someone could be anywhere along this scale, though. You may have noticed that some people are very, very masculine, and some are very, very feminine. This may apply to either men, or women. You can have a hyper masculine women, or a hyper feminine man. Similarly, you can have an extremely masculine man, and feminine woman. So, along this scale, you'd have to have numerous points where someone could land, which would allow for the various demarcations of where they feel they fit as a gender.
Then you have to have another scale, parallel to that, or perhaps intersecting with it, which represents sex. This one would not be something you'd be able to self identify. Not scientifically speaking, anyway. You'd probably need tests done on your chromosomes to see exactly where you fit on this scale, and whether it would jive with the other scale or not, I don't know. But that would be interesting to see.
Personally, if you look at me, I look very much like a man. I'm hairy all over, but bald on top... I've got a gut, and beard, and just a general manly shape to me. But, as for how I feel... well, I'm not the most masculine man you'd ever meet. I can be fairly masculine, but sometimes I'm less so. On a masculinity scale, from 1 to 10, I'd probably put myself at around 6 or 7.
Now, the last part of my scale, would be another intersecting line. So, if you can imagine a sort of jack, like kids play with: Three intersecting lines, all coming from different axis. That's how I picture this. This last part of the scale would be orientation. This one would be self-identified, and probably less than scientific, but there are ways of making it scientific, if you ever wanted to go to that extent. But this would be based solely on attractions. Not on past experiences. Who are you attracted to? For some people there may be some fluidity to this answer, and they have to take that into account. If you wanted to get scientific with this, you'd have to implement a plethysmograph, and measure arousal states to various erotic stimuli.
With all of these scales, though, what you would be defined as, may not be pinpointed on the line, but more of a general highlighted area. Labeling many people would be virtually impossible. Part of my point here, though, is that sex, gender, and orientation, are all rather complex. For some of us they can be fairly easily determined, but for others, it's not so simple, or perhaps not so simple given our society's limited understanding of these things. I'm sure books could, and have been written on this topic, and I've only barely brushed the surface. I mainly wanted to address how this related to Kinsey's scale, and how limiting that scale was in applying labels to people. Not everyone is able to find a label that will stick. But who cares? Who the fuck needs labels, anyway?