Leaving aside marriage & pensions (resolved) - ECHR (Goodwin & I v United Kingdom [2002] 2 FCR 577) ruled that a trans person's inability to change the sex on their birth certificate was a breach of the European Convention on Human Rights (Art. 8 & 12).
Now, 18 years later - when/why are people being required to show their birth certificates? This is probably an ignorant question - I was born abroad and my foreign bc is useless in the UK; I've only ever used it to apply for a passport (to prove my parentage) - otherwise I show my passport and some proof of UK residence.
As I understand it, no birth cert issued by any country of the UK is an identity doc (no pics). For people born in or after 1983, it's not proof of citizenship. So it's proof of age (along with a matching pic ID or equivalent) - and what else?
I can see how in the late '90s/early '00s when Christine Goodwin was having issues, a birth certificate might be required for any number of things like proving right to work in the UK, renting an apartment, opening a bank account, applying for a loan, getting married, etc. Are birth certificates still accepted as de facto proof of UK citizenship/right of abode even after the British Nationality Act 1981 (effective 1983) abolished blanket jus soli/birthright citizenship?
I understand not everyone wants or needs a passport: they're expensive, bulky, difficult to replace, and people have issues re the biometrics, but - couldn't a lot of the "need to change my birth certificate" issues today be solved by making available an optional, non-biometric picture ID card - government-issued and free on request with assistance to gather the required documentation - that proves identity, citizenship, and birthdate, but omits sex altogether?