NHS England is being taken to court for failing to offer fertility services to transgender patients.
The Equality and Human Rights Commission will take legal action, arguing that not offering treatments equally to patients restricts their options for reproduction.
By doing so before undergoing gender reassignment, trans people can choose to have their biological children via surrogacy later in life, although this is an expensive process.
NHS England states it is not its responsibility to ensure that fertility treatment is available to all patients.
A spokeswoman for NHS England told the Guardian: “NHS England has responded in detail to the EHRC explaining why we believe their request is both misjudged and potentially unfair to NHS patients. If, however, they still decide to sue the NHS, the courts will consider the matter in the usual way.”
Trans patients already face difficulties in seeking medical help, with a PinkNews exclusive discovering last year that some are forced to wait nearly three years for an appointment with the NHS.
A top gender doctor told PinkNews earlier this year that claims of insufficient capacity in the NHS to deal with the number of people questioning their gender identity were besides the point, and that the healthcare system simply had to re-adjust for the growing numbers.
Last month, EHRC chief executive Rebecca Hilsenrath said: “Our laws and our values protect those who seek treatment for gender dysphoria.
“This means that where appropriate, treatment should be made available in order to ensure that access to health services is free of discrimination.
“A choice between treatment for gender dysphoria and the chance to start a family is not a real choice,” she added.
“We have asked NHS England to reflect on the true breadth of their statutory mandate and the impact on the transgender community of these outdated policies.”
NHS England responded by saying that the watchdog had “misplaced their fire” and should instead be targeting government ministers to change the policy.
A spokesperson said: “Decisions on which services are commissioned by NHS England are taken by ministers based on advice from an independently chaired panel of health experts and patient representatives, using a process set out in primary legislation.”