The National Health Service (NHS) has been asking patients to choose from 12 genders before attending hospital appointments.
Patients have also been asked to choose from 159 religions and 10 sexual preferences.
The data has been described by critics as “bizarre” and “confusing”.
Some patients were even asked if they are a "Goddess, Satanist or Druid" before accessing care.
Guy's and St Thomas' NHS Trust and an inset of the MyChart app
PA/NHS
The questions are asked to patients when users register with an online portal.
The portal enables patients to access hospital appointment details, test results and medical records.
It is not compulsory to answer the questions but patients receive repeated reminders if they opt not to fill in the personal information.
Gender options include male, female, genderfluid, questioning, agender, non-binary, demiboy and demigirl.
Sexual preferences range from pansexual, bisexual, gay, heterosexual, lesbian, queer, questioning, unsure or asexual.
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Royal Brompton Hospital
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Patients are also asked to input their “sex assigned at birth” and “legal sex”.
The questions are asked as part of MyChart’s registration process.
MyChart is run by US-based health software firm Epic and used by 160 million patients worldwide.
Epic previously explained it introduced separate categories after a software developer, who is a transgender woman, received a hospital letter addressed to a “Mr”.
It said: “Lack of accurate information related to patients’ sex and gender identity can result in adverse health outcomes.”
The system was introduced at Guy’s and St Thomas’ NHS Foundation trust and King’s College Hospital NHS Foundation trust in October.
An NHS nurse walks through the waiting room in Outpatients Department
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Dennis Reed, director of Silver Voices, a campaign group for the over 60s, added: “Silver Voices is a strong supporter of equal rights but this is wokery to the nth degree.
Why on earth does the NHS need to know whether someone is a bisexual Methodist before an outpatient hospital appointment is made?
“People will feel obliged to answer all the questions so that there are no obstacles to them getting an early appointment, but this questionnaire is more complex and intrusive in some ways than the Census.
“We would have serious concerns on how this information will be used by the NHS, whether it will be divulged to private contractors, and the implications for confidentiality and personal security if the system is hacked.”
Lottie Moore, head of biology matters at the conservative Policy Exchange think tank, also said: “Gender identity ideology has been stitched into the very fabric of our public health system without public consensus.
"When it comes to healthcare, biological sex is vitally important, and it is crucial that NHS Trusts know the sex of their patients.”
Moore added: “Providing so many dubious identity options will likely be to the detriment of those without English as a first language and the elderly.
"NHS Trusts must stop playing identity politics and start prioritising patient dignity, safety and privacy.”