Just mark "X" on that passport, sir -- I mean ma'am.

At a time when sexual identities are increasingly -- well, confused -- the Australian government is stepping up to the plate.
Transgender people, and those of "ambiguous sex" -- whatever that means -- will now be permitted to officially declare their gender as "indeterminate" on travel documents. The choice will be indicated on the passport with an "X", says the BBC. Formerly, passport holders whose gender was different from that of birth were required to undergo full sex reassignment surgery before updating their records.
The only unresolved question is how immigration officials will address such people as they pass through customs control. Perhaps some combination of Mr./Mrs./Ms./It.