The authorisation applies to a person who initially requested to be described as male following a hormone treatment, but later regretted this and appealed to the court.
The case is currently sealed, the Superior Court of Justice said in a statement.
Nancy Andrighi, one of the judges in the panel and the case rapporteur, described the issue as dramatic in her ruling.
“This human being must be suffering greatly. To undergo surgery, take hormones, become what she thought would be good for her and then realise it was not the case,” Andrighi wrote. All other four judges of the panel agreed. (AP) DIV DIV