Ok to alleviate some questions here:
Difference between "sex" and "gender".
Gender being the scientific term - incredibly rare for it not to be binary: male/female. That's "what" you are.
Sex is how you consider yourself. "Who" you are. People who have a male gender, but have always believed themselves to be female for example. Thus you can have a different sex than gender (and some people rectify that with surgery).
Also sexuality is rarely a binary thing. Another aspect being who you are attracted to.
It is fairly well believed that as opposed to gay/straight there is a sliding scale everyone falls on, the majority of people being close enough to straight to not need to worry about the difference away from the end of the scale. Similar with the gay end of the scale, but plenty of people being right there in the middle or varying deviations along it.
That's not even yet giving the option for a "zero" response for non-sexuals.
So a simple 8 option technically doesn't come close to covering every aspect of the omni-directional graph you could derive for sexuality.
One which has to define the difference between a lesbian woman and a straight man born with a female gender.
As well as grades of sexuality: from excessively sexual to non-sexual.
Or on as many tangents as you like - sexuality towards animals perhaps.
However there really are enough options there to cover nearly all common areas of the graph.
All in all, nice blog.