From the Sunday Times:
For the first time in decades there is a new title to join Mr, Mrs, Miss and Ms: the gender-neutral “Mx” as an honorific for transgender people and anyone else who does not identify with a particular gender.
Seems like a useful addition to the English language. It doesn’t have much traction in the US (yet), but the new honorific has been gaining acceptance in the UK:
Government departments, councils, high street banks, some universities, Royal Mail and driving licences all now accept Mx.
Apparently it is pronounced mux or mix. Now you can start using it!