I think it's misleading to refer to a "third gender". If there were a "third gender", why wouldn't there be a "fourth" one and a "fifth" one? According to an in

I think it's misleading to refer to a "third gender". If there were a "third gender", why wouldn't there be a "fourth" one and a "fifth" one? According to an international standard there's a third option for the field labelled "sex", and the meaning of that third option is "not specified". So it's not a "third sex". See the references and external links at the bottom of https://en.wikipedia.org/wiki/Machine-readable_passport https://en.wikipedia.org/wiki/Machine-readable_passport Interestingly, civil servants working for the British government like to use the expression "third sex" (or "gender") when rejecting petitions for there to be a third option on British passports. People ask: please can we have the option to not specify our sex on our passports? And the government responds: we reject the notion of a third sex!