Actually, it’s not a test. It’s a program that looks at your browser history, then matches it to actual website usage patterns to make an estimate.
It’s wrong, of course, at least in my case. It says:
Likelihood of you being FEMALE is 66%
Likelihood of you being MALE is 34%
And I’m a guy. But a gay guy, so maybe the percentages are trying to estimate that as well, who knows?
So go here, and post your results!