Good timing: the Internet Identity Workshop is thinking about exactly these kinds of things right now!
The trick is to not assert cultural standards for identity. As we know from Facebook’s “authentic name” policy and its affect on the drag community, there are nuanced issues involved in identity that evolve over time. A government-issued name often isn’t appropriate.
Kaliya-IdentityWoman has written lots of great stuff about this, and is heavily involved in the identity community.