The European Court of Justice (ECJ) on Thursday ruled that European Union (EU) nations must provide transgender citizens with identification documents reflecting their "lived gender" rather than their gender at birth.

Bulgaria's Supreme Court of Cassation (SCC) referred the case to the ECJ, saying it was unclear whether Bulgaria could issue such documentation to a citizen who had changed their sex.

That conclusion came as Bulgaria's top court considered whether the government in Sofia could legally change the documents of an individual born a man but now identifying as a woman.

Lower courts in Bulgaria had determined that the country's officials had no right to change the individual's name, gender or national registry PIN.

The Luxembourg-based ECJ ruled that documents not reflecting an individual's lived gender identity could cause "considerable inconveniences" during travel, as well as in other daily situations.

The ECJ said honoring citizen's lived gender allows them to travel more easily within the bloc while emphasizing that EU law supersedes national law across the EU.

"Member state legislation which does not permit the amendment of the gender data of one of its nationals who has exercised his or her right to freedom of movement is contrary to EU law," read an ECJ statement.

The case, which began in 2017, now returns to Bulgaria's courts where a path to providing the proper documentation must be found.

The ECJ's ruling will also impact other EU nations that have so far refused to issue passports reflecting anything other than a person's gender at birth, such as Hungary and Slovakia.

Edited by: Louis Oelofse