The Civil Code was amended by Law 13/2005 to allow for same sex marriage. This law was challenged before the Constitutional Court by more than 50 Deputies of the Popular Party. The applicants claimed that the recognition of same sex marriage clashed, inter alia, with Article 32 of the Spanish Constitution, which sets forth that men and women have the right to marry.
The Spanish Tribunal Constitucional followed an evolutionary interpretation of the Constitution and held that Article 32 of the Constitution did not prevent the legislator from passing a law to allow for same sex marriage . The Court indicated that the recognition of same sex marriage was a legislative option supported by the principle of equality, but failed to ground its decision upon the right to non-discrimination on the basis of sexual orientation.
The Tribunal Constitucional made use of comparative law, by making reference to the legislation and court decisions in other countries. The Tribunal initially referred to a Privy Council precedent solely to borrow the image of the Constitution as a “growing tree,” but it then mentioned the use of this analogy in the Canadian Supreme Court’s judgment on same-sex marriage, displaying a clear comparative effort used to support the assessment of the very legal point it was seized of. Similarly, the Tribunal introduced a full overview of the jurisdictions recognizing same-sex marriage, either under their laws or subsequent to a judicial decision (see the reference to the Massachusetts Supreme Court and the Constitutional Court of Slovenia
Also, the Tribunal Constitucional opted for a consistent interpretation of Article 32 of the Constitution in light of the ECtHR’s case-law. In Schalk and Kopf v. Austria, the Strasbourg Court had issued an evolutionary interpretation of Article 12 ECHR, drawing support from the literal tone of Article 9 of the EU Charter of Fundamental Rights, which does not explicitly refer to men and women.