Family law (2023): Validity of marriages: Marriage law

Marriage is an institution that is historically filled with restrictions. From age, to gender, to social status, various restrictions are placed on marriage by communities, religious institutions, legal traditions and states.

Marriage age.

The minimum age at which a person is able to lawfully marry, and whether parental or other consents are required, vary from country to country. In the U.S. the minimum age for marriage without parental and or judicial approval is 18 except for Nebraska (19) and Mississippi (21); but most states allow exceptions to the general minimum age in some circumstances (see Marriage age in the United States). In England and Wales the general age at which a person may marry is 18, but 16- or 17-year-olds may get married with their parents' or guardians' consent. If they are unable to obtain this, they can gain consent from the courts, which may be granted by the Magistrates' Courts, or the county or High Court family divisions.

Gender restrictions.

Legal, social, and religious restrictions apply in all countries on the genders of the couple.

In response to changing social and political attitudes, some jurisdictions and religious denominations now recognize marriages between people of the same sex. Other jurisdictions have instead "civil unions" or "domestic partnerships", while additional others explicitly prohibit same-sex marriages.

In 1989, Denmark became the first country to legally recognize a relationship for same-sex couples, establishing registered partnerships, which gave those in same-sex relationships "most rights of married heterosexuals, but not the right to adopt or obtain joint custody of a child". In 2001, the Netherlands became the first country in the world to legalize same-sex marriage. As of date, marriage between same-sex couples is legally performed and recognized in 34 countries, namely the Netherlands, Belgium, Spain, Canada, South Africa, Norway, Sweden, Portugal, Iceland, Argentina, Denmark, Brazil, France, Uruguay, New Zealand, Luxembourg, the United States, Ireland, Colombia, Finland, Malta, Germany, Australia, Austria, Taiwan, Ecuador, United Kingdom, Costa Rica, Chile, Switzerland, Slovenia, Cuba, Mexico and Andorra.

Civil union, civil partnership, domestic partnership and registered partnership statuses offer varying legal benefits of marriage. As of 5 June 2023, countries that have an alternative form of legal recognition other than marriage on a national level are: Bolivia, Croatia, Cyprus, the Czech Republic, Estonia, Greece, Hungary, Italy, Liechtenstein, Monaco, Montenegro and San Marino.

Further religious conflicts.

These developments have created a political and religious reaction in some countries, including in England, where the Church of England, after long debate, officially banned blessings of gay couples by Church of England clergy, and in the United States, which continues to experience conflicts, based upon religious grounds.

Kinship restrictions.

Kinship is two people that are related by blood or adoption, such as brother, sister, mother, father, aunt, uncle etcetera. No European country prohibits marriage between first cousins. The U.S. is the only western country with cousin marriage restrictions. Societies have often placed restrictions on marriage to relatives, though the degree of prohibited relationship varies widely. In most societies, marriage between brothers and sisters has been forbidden, with ancient Egyptian, Hawaiian, and Inca royalty being prominent exceptions. In many societies, marriage between first cousins is preferred, while at the other extreme, the medieval Catholic Church prohibited marriage even between distant cousins.