Transgender people are waiting up to two and a half years for initial consultations at NHS gender identity clinics.
This is despite an NHS England pledge in 2016 to bring waiting times to below 18 weeks by 2018.
The average wait from receiving a GP referral to getting a first appointment is 18 months.
NHS England said providers were "working to expand treatment teams and reduce waiting times".
The clinic with the shortest waiting time is Sheffield Health and Social Care NHS Foundation Trust Gender Identity Service at 51 weeks.
However, Northamptonshire Healthcare NHS Foundation Trust Gender Clinic said its current waiting time for an initial appointment is two and a half years.
It added "demand outstrips supply" and it wants to "ensure that the first clinician the patient sees will be one that can complete a diagnostic assessment to start the treatment pathway".
The BBC asked NHS England for the number of referrals over the last three years but the information was not made available.
One clinic in London said there was an "unprecedented" increase in the number of referrals to them.
The Tavistock and Portman NHS Foundation Trust: Gender Identity Clinic for Adults said there has been a rise of 55.25% in referrals made, with 295 in November 2017 compared to 163 in November 2016.
'Life or death'
Ethan Evans, who is from Saltash, Cornwall, but lives in London, visited a psychologist in 2015 after "fighting and suppressing" his feelings since the age of 10. He had to wait nearly two years to have his referral go through in 2017.
He said: "You've gone through the whole process of deciding that is what you are, you are transgender and then you have to wait a year and a half to two years for somebody else to go 'yeah that's right'.
"It has taken a toll psychologically on me. The wait is so long and it is literally a life or death thing."
Ethan is now on another waiting list for surgery to complete his transition so "in the summer I'll be able to actually wear a T-shirt and feel comfortable".
Transgender people are usually required to undergo hormone therapy for 12 months, alongside regular GP check-ups, before any further consultations.
The Beaumont Society, a support group in the UK for the transgender community, said the waiting times are "heartbreaking".
"Having summoned up the courage to share the knowledge with others that they are trans only to be told that you cannot get help for over two years is a cruel blow," it added.
The average waiting time comes from information given by seven out of the eight NHS gender identity clinics in England.
Northumberland, Tyne and Wear NHS Foundation Trust Northern Region Gender Dysphoria Service said it can only provide numbers through a Freedom of Information request.
NHS England added that "demand for gender identity services continues to rise as more people feel able to come forward for support and treatment".