The referendum in Romania this weekend that could see the conservative country ban gay marriage underlines the largely East-West split in Europe over same-sex unions.
In 2001 The Netherlands became the first country in the world to allow gay and lesbian couples to marry in a civil ceremony.
Fifteen European countries have followed: Belgium, Britain (but not Northern Ireland, which only accepts civil partnerships), Denmark, Finland, France, Germany, Iceland, Ireland, Luxembourg, Malta, Norway, Portugal, Spain and Sweden, with Austria due to join next year.
In several of these countries, gay marriage had been preceded by civil partnerships, which come with fewer rights, Denmark being the pioneer in 1989.
Some European countries still only allow such partnerships, rather than marriage, including Croatia, Cyprus, the Czech Republic, Greece, Hungary, Italy and Switzerland.
Slovenians also allow civil partnerships but in 2015 rejected in a referendum a proposal to legalise gay marriage.
In June 2018 the Czech government backed draft legislation that would make the country the first post-communist member of the European Union to legalise same-sex marriage.
But most Eastern European countries allow neither gay partnerships nor marriages, including Bulgaria, Latvia, Lithuania, Poland, Romania and Slovakia.
In 2014 Estonia became the first former Soviet republic to authorise same-sex civil unions.
In Russia homosexuality was considered a crime up to 1993 and a mental illness until 1999. Now legal, a 2013 law however punishes the promotion of homosexuality among minors.
Western Europe also leads the way on the rights of same-sex couples to adopt children, whether within marriage or civil partnerships.
This is allowed in Austria, Belgium, Britain, Denmark, France, Germany, Malta and The Netherlands, Spain and Sweden.
Other countries, like Finland and Slovenia, allow gay people to adopt their partner’s children.
Medically Assisted Procreation (MAP) is allowed for lesbian couples in Austria, Belgium, Britain, The Netherlands, Spain and the Nordic countries. France is examining whether to make such a move.
Most European countries however ban surrogacy although the use of surrogate mothers is allowed – as long as they are not paid – in Belgium, Britain and The Netherlands. In an exception, Greece in 2014 authorised paid surrogacy.
Further afield, homosexual couples can also marry in Canada since 2005 and in the United States since 2015, as well as in four Latin American countries: Argentina, Brazil, Colombia and Uruguay.
South Africa in 2006 became the sole African nation to allow gay marriage.