European pioneers
In April 2001 the Netherlands became the first country in the world to allow gay and lesbian couples to marry in a civil ceremony.
Twelve European countries followed: Belgium, Britain (except Northern Ireland), Denmark, Finland, France, Iceland, Ireland, Luxembourg, Norway, Portugal, Spain and Sweden.
In Germany, the upper house had already approved the bill, and the measure is now expected to enter into force before the end of the year.
Some European countries only allow same-sex couples to enter into civil partnerships, including Austria, Croatia, Cyprus, the Czech Republic, Greece, Hungary, Italy, Malta and Switzerland.
In October 2014, Estonia became the first former Soviet republic to authorize this type of civil union.
Many eastern European countries -- including Bulgaria, Latvia, Lithuania, Poland, Romania and Slovakia -- deny homosexuals the right to marry or enter into unions.
In December 2015, Slovenians voted in a referendum against efforts by their national parliament to legalize gay marriage.
About 15 western European countries allow same-sex couples to adopt children, whether within marriage or civil partnerships. They include Belgium, Britain, Denmark, France, the Netherlands, Spain, and Sweden. Other countries, including Finland, Germany and Slovenia, let gay people adopt the children of their partners.
Progress in the Americas
Canada led the way in North America, authorizing same-sex marriage and adoptions in June 2005.
In the United States, a Supreme Court decision in June 2015 legalized gay marriage nationwide.
Mexico's federal capital led the way in Latin America, authorizing civil unions in 2007 and full marriages in 2009.
Same-sex marriages are also legal in Argentina, Brazil, Colombia and Uruguay.
Chile's civil union law recognizes same-sex couples, and Costa Rica allows them to share health and pension benefits.
Rare in Africa, Asia and Middle East
On the African continent, where around 30 countries ban homosexuality, only in South Africa can gays legally marry and adopt children.
In the Middle East, Israel leads in terms of respect for homosexual rights, recognizing gay marriages performed elsewhere even though such marriages are not performed in Israel itself. Gay couples can jointly adopt children.
In the Asia-Pacific region, the only country that allows gays to marry is New Zealand, which passed a law in April 2013.
Several Australian states practice civil unions, which are not recognized nationwide. But adoptions by gay parents are legal.
In May, Taiwan's constitutional court ruled against laws that prevent same-sex unions and gave the government two years to draft new legislation.