A transsexual who has been living as a woman for over 10 years is asking the High Court to rule that she is entitled to NHS breast augmentation surgery.
The woman, of Reading and referred to as C, is fighting a test case against a continuing refusal by West Berkshire PCT to fund her treatment.
She is arguing that it amounts to a violation of her human rights and unlawful sex discrimination.
The PCT said there were no health reasons for the procedure.
The judge, Mr Justice Bean, was told C, who cannot be named for legal reasons, should not be compared with a woman unhappy with her body image who wanted larger breasts.
Barrister Stephanie Harrison, said C's move to a female identity and emotional well-being were at stake.
However the PCT said the surgery would be "purely for cosmetic reasons".
It also stated there was lack of evidence that the procedure would improve C's health.
Ms Harrison accused the PCT of persisting with a flawed policy and said its decision should be quashed.
She said her client had, despite hormonal therapy since 1996, "not produced in any significant way breasts that are appropriate to her size and frame".
She had faced problems of hostility and abuse in public because she was not yet seen as a woman.
"Youths have called her all kinds of names because they perceive her not to be a woman," said Ms Harrison.
C was diagnosed with gender dysphoria over a decade ago, the court heard.
She is now under the care of the specialist gender identity clinic at Charing Cross hospital in west London.
She initially applied, with the backing of her doctors, for breast augmentation surgery in 2006, but the PCT refused - and has refused ever since - to fund the treatment.
C wants to eventually to complete her move to her female identity with surgery to remove her male genitals, the court heard.
But she was not yet in a position to do so because she had not yet "achieved in her own mind the conditions necessary for becoming physically female because of the inadequate breasts produced by hormonal therapy."
The case, which C has brought with the assistance of legal aid, is expected to last three days.