Civil marriage in Mexico has two notable influences that affect how it functions even today.¹ The first is Catholicism’s influence in the inception and understanding of marriage in Mexican society. The second, closely related to the first, is the influence of the Second Scholastic, and through them, of Thomism and Aristotelian reasoning, in the legal construction of marriage.

The first civil marriage in Mexico was actually a catholic institution. When the nascent Mexican Nation-State issued in 1857 its first law regulating the Civil Registry, it established that couples should get married before the Catholic Church. If they wanted their unions to have “civil effects,” they had to register them before the Civil Registry. When Mexico finally issued a law 2 years later that regulated marriage, including who could get married, how, and why, it replicated the institution of catholic marriage. The statute was passed in the context of the “wars” between the Mexican State and the Catholic Church. During this time, Mexico published a series of statutes, called the Leyes de Reforma (Laws of Reform), through which it tried to dismantle the power of the Catholic Church. Among other actions, the government seized control of the Church’s properties and enacted the Civil Registry Law and the Law of Marriage, areas previously controlled by the Church. Replicating catholic institutions through legal secular reforms allowed people to comply with Mexico’s regulations while remaining truthful to their faith. There was an acceptance of the catholic concept of marriage.²

The convergence between the catholic and civil concepts of marriage did not reside solely on the actual definitions, and rights and obligations, that each established. The basic structure of marriage, how it was defined and understood, was the same in the catholic and civil marriage institutions. Liberals followed the French Napoleonic Code in their regulation of marriage, while the Catholic Church followed Canon Law. Historian James Gordley claims that both the Napoleonic Code and Canon Law came from the same place: a conceptualist and teleological method of reasoning that Aquinas, following Aristotle, used on marriage, and, that the Second Scholastic, following Aquinas and Aristotle, used to build a doctrine of contract law.³ This doctrine of contract law survived up until the French Civil Code and even today in most of Mexican civil and family law. It is not that individualism and other modern values did not alter the way contract law or marriage, specifically, operated. The logic of these legal institutions, however, and not just only moral or religious beliefs about marriage, made its reform harder.

The first big change to marriage came in 1914 when divorce was understood as the dissolution of the marriage bond and individuals could remarry. The amendment, however, allowed for no-fault divorce only in cases of mutual consent. Otherwise, divorce was granted if there was fault by one of the parties. Fault basis for divorce meant that the “realization of marriage’s ends [were] impossible or unjust” or the “discord of the spouses [was] irreparable.”⁴ The idea of marriage as a union that could only dissolve if the realization of marriage became impossible changed in 2008 when no-fault divorce was allowed.⁵ In the early years of the twentieth century, however, marriage suffered two other important changes. The first was the elimination of all distinctions between legitimate and illegitimate children. The second was the recognition of cohabitation between a man and a woman as another form of family formation. Concubinato, however, granted little rights to the couple.⁶ With time, female concubines started gaining more rights. In the 1973 Social Security Law, for instance, female concubines were included as beneficiaries of social security. Prominently, the female concubines had a right to receive a pension derived from her partners’ work disability, age retirement or death, in similar conditions as legal spouses.⁷ In 1983, the law established that concubines –men and women– had the obligation to provide each other economic support.⁸ In 2000, concubinato became a full-fledged alternative to marriage, when it was officially conceived as another source of kinship⁹ and was granted “all the rights and obligations inherent to the family, as applicable to them.”¹⁰ In 2006, thanks to the LGBT movement, Mexico City recognized civil unions as an additional option for couples, both of same and opposite-sex (“sociedades de convivencia”). The law stated that these societies would enjoy the same rights and obligations established for concubines.¹¹ The most prominent difference between concubinato and a civil union was its source of formation. While concubinato recognized an already established relationship between a man and a woman who had been living together for 2 years, or less if they had a child, a sociedad de convivencia was a contract that two people had to sign and register at a government office (not the Civil Registry).¹² These changes are important because marriage stopped being the “only moral way to found a family.”¹³

Adoption suffered changes as well. Legally established in 1917, it was originally conceived as an exclusive relationship between the adoptee and the person seeking to adopt.¹⁴ It did not extend to other family members (grandparents, brothers and sisters, etc.). It was not until 1998 that the law included for the first time “full adoption” (adopción plena). In this case, the relationship between the adopted child and the birth parents was extinguished. And the adoption created a filial relationship between the child, the adoptive parents, and their extended family.¹⁵ The recognition of adoption undermines marriage as the exclusive gateway to family formation by accepting that biological reproduction is not the only way to establish parenthood.

With regards to obligations between spouses, changes were triggered by a concern for women’s equality. Even in the Law of Marriage of 1859, lawmakers denounced how “in spite of the philosophy of the century and of the great progress of humanity, the woman, that precious half of the human being, still appear[ed] degraded in the old legislation.”¹⁶ One of the innovations of the 1870 Civil Code, for example, was to give the mother, along with the father, parental authority (patria potestad).¹⁷ Many other changes slowly happened throughout the years.¹⁸ In 1974 the Constitution was amended to include a provision that men and women were “equal before the law.”¹⁹ This constitutional amendment gave an important push for the amendment of most states civil codes in Mexico, specifically with regards to marriage. Equality was enshrined in the Constitution and in the civil codes before the amendment. Sex, however, had, until then, been treated as a justified reason to allow a differential treatment between men and women, particularly within marriage. The 1974 constitutional reform was introduced precisely to change this conception. This reform was later complimented in 1981, when Mexico also incorporated the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) into its law.²⁰ Article 16 of CEDAW explicitly established that States must take measures to “eliminate discrimination against women in all matters relating to marriage and family relations,” which includes granting them the same rights and responsibilities “during marriage and its dissolution” and “as parents.” This move is important because it shattered the “sexed” nature of marriage. Before, marriage had to be between a man and a woman because only a man and a woman together could fulfill marriage’s ends. They were “halves” that, when joined, embodied perfect “conjugal duality.” The man was in charge of providing for the family; the woman was in charge of taking care of the family. With equality, these roles could remain the same, or be reversed, or be distributed in other ways. This distribution had nothing to do with the sex of the person, but with their personality and interests.

One of the ends of marriage, since 1859, had been reproduction. The 1974 constitutional reform introduced, together with sex equality, the right of each individual to freely determine the number and spacing of his or her children. In response to the constitutional reform, the law established that, when it came to marriage, the right to decide the number and spacing of children had to be exercised jointly by the spouses.²¹ This norm survives until today. It has only been altered once, in the year 2000, when the law established that couples had a right to access “any method of assisted reproduction to achieve [having] their own offspring.”²² This was also the year in which the definition of marriage changed and it became the “free union of one man and one woman to form a community of life, in which both offer each other respect, equality and mutual aid, with the possibility of procreating children in a free, responsible, and informed manner.”²³ That same year, being incapable of copulating was no longer an impediment for marriage if the other spouse knew and accepted it. Historically, this can be viewed as the moment in which procreation stopped being one of the ends of marriage.

Originally infidelity was also grounds for divorce and adultery was a crime. In 1928, fidelity stopped being an explicit obligation of the spouses. Adultery was decriminalized in 2002 and infidelity stopped being a cause for divorce in 2008. With these changes there was no longer a link between the act of having sex and marriage. Additionally, in 2008 the Civil Code allowed people to change their birth certificate to reflect their sex change. This reform is notable for two reasons. The first is that it included no prohibition for trans people to get married. If a man became a woman and married a man, this became a valid marriage.²⁴ The second highlight of this reform is that if trans people were married at the time of their sex change, the procedure did not modify their civil status and the couple remained married in the eyes of the law. If a man, married to a woman, became a woman, the law accepted their marriage –or at least the “obligations” that spawned from it.²⁵ In the first case, if one considers that many trans people undergo surgery that affects their reproductive capacity, the law is implicitly sanctioning the disconnection between marriage and procreation. In the second case, the law is implicitly sanctioning the marriage that exist between two people that are now of the same sex.²⁶

In December 2009, the law was reformed once more, this time redefining marriage as “the free union of two people for the realization of a community of life, in which both offer each other respect, equality and mutual aid.”²⁷ It no longer included a mention of procreation, or sex diversity in the couple. Concubinato was also reformed to expand its effects to same-sex cohabitant couples. And, importantly, adoption was not reformed with the aim of excluding same-sex couples from being able to initiate an adoption process. With this reform, same-sex couples acquired the exact same rights as opposite-sex couples with regards to marriage and cohabitation.

In addition to several amendments triggered by social welfare reform, in 1974, the Constitution was amended to include the following norm: “[The law] must protect the organization and development of the family.” In that reform, article 123, section XXIX was altered and social security became a right of the worker “and [his or her] extended family.” The International Covenant on Civil and Political Rights, the International Covenant on Economic, Social, and Cultural Rights, and the American Convention on Human Rights became Mexican law in 1981.²⁸ Additionally, the General Health Law was passed in 1983.²⁹ It established that one of the objectives of the National Health System was to “promote the development of the family and the community.”³⁰ The law advanced maternal care,³¹ determined that “health, educational and labor authorities” had to support and promote…cultural activities destined to strengthen the family unit….,³² and dealt with families with drug addiction and disability issues.³³ In 2003, the General Health Law was reformed to create the System of Social Protection in Health, commonly known as the “popular insurance” (seguro popular). It was designed to reach the population that wasn’t being covered by the health insurance provided by social security. The “unit of protection,” however, became the family unit. It was not aimed at protecting the individual or the worker but the family unit, which could consist of: couples married or in concubinato, and “the father and/or mother” not joined in matrimony or in cohabitation.³⁴

With regard to housing, as early as 1972, the Institute of the National Fund for Workers’ Housing was created by law. The loans given to each worker were to be determined considering the number of family members each worker had.³⁵ In 1983, the Constitution was amended to establish that “every family ha[d] a right to enjoy dignified and decorous housing.” In 2006, the Federal Congress passed a law aimed at “establishing and regulating the national policy, programs, instruments and support so that every family might enjoy” this right.³⁶

Besides housing, health, and property protections, the other great source of support for families came through support for children. Since 1929, several associations were created for this purpose, such as the National Association for the Protection of Childhood, the National Institute for the Protection of Childhood, the Mexican Institute for the Assistance to Childhood and the Mexican Institution of Childhood Protection. The actions these institutes took ranged from giving mothers’ milk and school lunches, and trying to solve the problem of child abandonment and exploitation. The highlight of reforms in this area came in 1977 with the creation of the National System for the Integral Development of the Family –DIF, for its initials in Spanish– which, until today, is the organism in charge of taking care of the “most vulnerable” sectors of society, including children, the elderly,³⁷ and people with disabilities, and promoting policies for the “integration of the family.” They offered legal counseling for families; psychological attention and homes for children and teenagers; homes for the elderly, centers for rehabilitation of people with disabilities.³⁸ Since the 1980s, the government has had several programs that supply day-care facilities for mothers. All of these programs are administered through DIF.³⁹

To complete the protection of the family, there were also changes to the criminal law system. In addition to civil enforcement, not complying with the obligation of economic support became a punishable crime.⁴⁰ Homicides, assaults, rape and sexual abuse received higher sentences if committed against a family member.⁴¹ The crime of femicide was also punished with higher crimes if the perpetrator was emotionally involved with the victim.⁴² Family violence was defined as “the physical, psycho-emotional, sexual, economical, patrimonial violence […] that happens […] in or out of the home” against the spouse, concubine, an ascendant, a descendant, the adopted child, the adoptive parent, the ward, or the person with whom a civil union was contracted.⁴³ In all of these cases, the Criminal Code protects “the family” and not just the marriage bond.

In spite of all these changes to marriage and the family, marriage was still interpreted according to the functions it fulfilled in society. Decisions on marital rape, loss of parental rights and no-fault divorce show this contradiction between textual reforms to the law and legal reasoning based on traditional concepts of marriage and family.

The statutes on same-sex marriage and concubinato passed by Mexico City’s legislature were challenged through an acción de inconstitucionalidad (action of unconstitutionality), a judicial mechanism of abstract review that requires a supra-majority of 8 Justices –out of 11– to strike down the challenged law. Nine Justices voted in favor of upholding same-sex marriage and upholding same-sex couples accessing the adoption procedures.

The acción de inconstitucionalidad was initiated by the Attorney General of Mexico. It was not the only challenge against the reform. Six other States challenged it through a mechanism known as the controversia constitucional (constitutional controversy), which is designed to protect the constitutional division of powers and federalism, by allowing each level and power of government to challenge what they perceive to be an infringement on their own powers by other levels and powers of government.⁸⁶ These States argued that the Mexico City reform would force them to recognize a type of marriage that their legislation either did not recognize or explicitly prohibited. All six of these challenges were ultimately dismissed. The reason was simple: it was the Federal Constitution, in its article 121, clause IV, that forced them to recognize Mexico City’s marriages.

The Attorney General’s brief challenged same-sex marriage, but not same-sex concubinato. He argued that he was not against legal recognition of same-sex relationships but only against their recognition through marriage. Same-sex couples, he sustained, should be regulated through civil unions, an institution more “appropriate” for them. The brief did not argue that sexual preference or orientation should not be treated as a suspect class when arguing discrimination. His position was that not allowing same-sex couples to marry was an authorized differentiation, even within the doctrine of the right to non-discrimination. The law, the Attorney General argued, should treat equally those who are equal and unequally those who are unequal. Homosexuals and heterosexuals, for the purposes of marriage, were not equal. The brief also argued that marriage was designed for procreation, which he understood in strict (hetero)sexual terms. Thus, same-sex couples could not “fit” into marriage, since same-sex couples could not sexually reproduce with each other. The brief also argued that this understanding of marriage was reflected in article 4, paragraph 1 of the Federal Constitution, which states that the “law must protect the development and organization of the family.” He also argued that this was the concept of marriage included in international treaties such as the Universal Declaration of Human Rights, the American Convention on Human Rights and CEDAW. Finally, he argued against same-sex couples having access to adoption based on the suffering these children would endure from social discrimination.

The Mexico City Government, on the other hand, made the case about family diversity. This was not, the City argued, just about LGBT families, but about all families that did not conform to the husband/father-wife/mother-(sexually produced) offspring model of the family. Its brief focused on three things: (1) tracking the sociological development of the family in Mexico and showing how today, family diversity is a fact; (2) holding that article 4, paragraph 1 of the Federal Constitution protected all types of families: straight, gay, two-parent, one-parent, no children, adopted children, etcetera; (3) and holding that the Universal Declaration of Human Rights, the American Convention on Human Rights, and CEDAW did not limit marriage to opposite-sex couples.