Dr Lydia Foy leaving the High Court after having her gender legally recognised
The legislation permits all individuals over the age of 18 to self-declare their own gender identity without testimony from medical professionals.
The bill also allows trans people to have their gender accepted by state bodies for all purposes, including the right to marry or enter into a civil partnership.
It means people who have transitioned can be issued with a new birth certificate and name, if they wish.
The law, which was passed in July 2015, made Ireland the fourth country in the world to recognise self-declared genders without the need for surgery or medical certification.
Figures provided to Anti-Austerity Alliance TD Ruth Coppinger by Minister for Social Protection Leo Varadkar show his department issued 149 gender recognition certifications between September 2015 and the end of June 2016.
While it was largely welcomed by transgender advocacy groups, the Gender Recognition Act also came under criticism for requiring people aged between 16 and 18 to undergo medical observation before having their preferred gender recognised.
Under the legislation, trans teenagers must also obtain parental consent and a court order to qualify for certification.
The bill additionally excludes children under the age of 16 from legal recognition.
These provisions are due to be considered as part of a review of the act, scheduled to take place within two years of its commencement.