The degree of legal recognition provided to transgender people varies widely throughout the world. Many countries now legally recognise sex reassignments by permitting a change of legal gender on an individual's birth certificate. Many transsexual people have permanent surgery to change their body, sexual reassignment surgery (SRS) or semi-permanently change their body by hormonal means, hormone replacement therapy (HRT). In many countries, some of these modifications are required for legal recognition. In a few, the legal aspects are directly tied to health care; i.e. the same bodies or doctors decide whether a person can move forward in their treatment and the subsequent processes automatically incorporate both matters.