In some countries, a civil union is a contract between two people, which gives them rights similar to those they can obtain in marriage. In countries where it is allowed, a civil union is often available to people of the same sex; marriage is often limited to people of opposite sex. The first country to introduce civil unions was Denmark, in 1989. In Denmark, a civil union was limited to people of the same sex. These people got the same rights and duties than married people. In 2010, such couples were also allowed to adopt children. Since 2012, Denmark allows people of the same sex to marry, and the civil union is no longer available.