How many sex options should be available in a sign up form?

I found an Indonesian Digg clone website. When I get to the sign up form, the sex field is too...err...I run of out word to describe it....



I used to think 2 options (Male or female) are enough, but now, I know I am wrong. The most astounding option is actually 'None of the Above'.....hmm....my creativity fails me, I can't imagine what kind of homo sapiens would select the last option...