Should there be a third gender option on passports?

UK passports should allow people to define themselves as "X" as an alternative to male or female. It’s part of a five year plan announced today by Stonewall, a LGBT rights group, which argues it would benefit people who face difficulties at passport control.

Tara Stone, a member of the Stonewall Trans Advisory Group tells the Today programme this would give transgender people "an option that wasn't prescriptive" and helps "validate their identity".