Metro Bank can have a registered non-binary (someone who neither sees themselves as male or female) customer.
Not sure if this is already supported in Monzo and it wouldn’t make me unable to use it if not. Before the bank officially launches with a current account and begins marketing to the masses, it would be a good idea to position Monzo as an all-inclusive bank. This means when asking for an applicants gender, offer a third option other than male or female. Also when asking for their title Metro have allowed for the popular option of “Mx”.
As of today, its application forms will allow people to declare themselves as non-binary and use the title “Mx” rather than Mr, Mrs or Ms.