People should be able to choose X, M, or F as they prefer on passports in the mandatory sex field on passports. This would allow LGBTQ+ Britons to feel more comfortable about their passports. Already, in countries like New Zealand and Malta, X can be used instead of M or F on a passport.
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As gender in the public consciousness becomes a less static and binary thing, we would benefit immensely from allowing people to choose the letter that appears in the sex field on their passport to allow citizens of this country more comfort and confidence when showing their passport when necessary.