On: 33 Questions

[k__]

The question should be about biology, not stuff like gender. Biology solves this problem (most of the time)

[ronaldx → k__]

Not really. The stats have not been thoroughly calculated (to my knowledge) but here is an attempt: http://www.isna.org/faq/frequency

Not XX and not XY: one in 1,666 births

Klinefelter XXY: one in 1,000 births

There are other relevant cases, not necessarily measured here, like mosaicisms and chimerism.

"Do you self-identify as female?" is a more answerable question.

[k__ → ronaldx]

but doesn't 1:1666 mean the success rate is more than 99%?

Asking about the posession of an XX chromosome should separate the people almost 50:50, the rest is something else.

On the other hand, maybe there are just <1% people who don't identify them self with being male or female, so the questions would make no difference...

[ludston → k__]

| On the other hand, maybe there are just <1% people who don't identify them self with being male or female.

Huzzah for logic. But note that the question was, "Do you have 1 apple" and not, "Choose a statement: 'I have 1 apple', 'I have 2 apples'"

[k__ → ludston]

True story, but "Do you have XX-Chromosomes?" would do the trick and cut the mass of people at around 50%.

[ebiester → k__]

All that matters is that the answer stays consistent for purposes of the 33 questions.