OII Europe submitted a letter of observations to the Bulgarian Constitutional Court with contextual information regarding practical obstacles faced by intersex people seeking legal gender recognition, and in the matter of the interpretation of the concept of sex under the Constitution. The Supreme Court of Cassation asked the Constitutional Court how legal gender recognition of a person is compatible with the Bulgarian Constitution, namely the right to private life (Art 32(1)) as well as Bulgaria’s international obligations arising out of the European Convention on Human Rights and EU law.