NATIONAL LEGAL SERVICES AUTHORITY (NALSA) VS UNION OF INDIA case was filed by the NALSA to legally recognize persons who fall outside the male/female gender binary, including persons who identify as “third gender”.  

• This was a landmark decision where the apex court legally recognised “third gender”/transgender persons for the first time and discussed “gender identity” at length.  
• The Court recognised that third gender persons were entitled to fundamental rights under the Constitution and under International law.  
• Further, it directed state governments to develop mechanisms to realise the rights of “third gender”/transgender persons. 

Source: Laxmikanth