German Chancellor Angela Merkel has softened her opposition to gay marriage, which is legal in about 20 countries around the world, 13 of which are in Europe.
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.
Some European countries only allow homosexuals to enter into civil partnerships, including Austria, Croatia, Cyprus, the Czech Republic, Germany, Greece, Hungary, Italy, Malta and Switzerland.
In October 2014, Estonia became the first former Soviet republic to authorise 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 legalise 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, authorising same-sex marriage and adoptions in June 2005.
In the United States, with gay marriages still banned in 14 of the 50 states, a Supreme Court decision in June 2015 legalised gay marriage nationwide.
Mexico’s federal capital led the way in Latin America, authorising 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 recognises 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, recognising 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 recognised 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.