Amparo en Revisión 165/2021: Same-Sex Marriage Rights

Introduction

Amparo en Revisión 165/2021 is a landmark judgment of the First Chamber of the Supreme Court of Justice of the Nation (SCJN) that confirmed the right to same-sex marriage across all Mexican states. Building on earlier jurisprudence, the ruling established that state civil code provisions limiting marriage to opposite-sex couples violate constitutional guarantees of equality, non-discrimination, and the free development of personality.

Background

Prior to the SCJN’s jurisprudence on same-sex marriage, Mexican states uniformly defined marriage as the union of a man and a woman. In 2010, Mexico City became the first jurisdiction to legalize same-sex marriage. The SCJN’s 2015 resolution in Acción de Inconstitucionalidad 2/2010 declared that same-sex marriage bans violated the Constitution, but the ruling technically only applied to states that had filed challenges. Subsequent amparo judgments extended the right to same-sex couples on an individual basis.

The 2021 Ruling

In Amparo en Revisión 165/2021, the SCJN held that any law prohibiting same-sex marriage is unconstitutional and that state civil registries must process same-sex marriage applications on equal terms. The Court reasoned that: the right to marry is a fundamental right protected by Article 4 of the Constitution; discrimination based on sexual orientation violates Article 1’s equality guarantee; and the free development of personality (libre desarrollo de la personalidad) encompasses the right to choose one’s marital partner.

Legal Impact

The ruling established binding precedent (jurisprudencia) requiring all state authorities to recognize same-sex marriage. The jurisprudencia was published as Tesis 1a./J. 84/2021 (10a.), which declares that civil codes and marriage laws prohibiting same-sex marriage are unconstitutional and that judicial authorities must apply the ruling to all pending cases. Following the ruling, virtually all Mexican states have amended their civil codes to permit same-sex marriage.

Broader Significance

The case exemplifies the SCJN’s role in expanding rights through constitutional interpretation, particularly for historically marginalized groups. It demonstrates the effectiveness of the amparo remedy in achieving systemic legal change, as individual amparo decisions are aggregated into binding jurisprudencia that governs all future cases.

Conclusion

Amparo en Revisión 165/2021 marks the culmination of the SCJN’s jurisprudence on marriage equality, affirming that the right to marry is a fundamental right that applies equally to same-sex and opposite-sex couples. The case illustrates the power of constitutional adjudication to advance equality and non-discrimination.