Same-sex marriage, which Taiwan’s top court ruled in favour of Wednesday, is currently legal in around 20 countries around the world, 13 of which are in pioneering Europe.
Such unions are, however, still illegal in most parts of Africa and in the Middle East, where homosexuality is in some cases punishable by the death penalty.
The Netherlands in April 2001 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, Germany, Greece, Hungary, Italy and the Czech Republic.
Estonia became in October 2014 the first former Soviet republic to authorise this kind of civil union.
Many eastern European countries — including Bulgaria, Latvia, Lithuania, Poland, Romania and Slovakia — still deny homosexuals the right to marry or enter into unions.
Slovenians in December 2015 voted in a referendum against efforts by their national parliament to legalise gay marriage.
Some 15 western European countries allow same-sex couples to adopt children, whether within marriage or civil partnership. They include Belgium, Britain, Denmark, France, the Netherlands, Spain, and Sweden. Others like Finland, Germany and Slovenia allow gay people to adopt the child of their partner.
Ten countries allow lesbian couples to conceive children with the help of assisted reproductive technologies (ART): Austria, Belgium, Britain, the Netherlands, Spain and the Nordic countries.
Surrogacy remains restricted across most of the continent.
Belgium, Britain and the Netherlands allow for volunteer surrogacy and in Greece, women can be reimbursed for the costs of carrying a child for someone else.
Progress in America
Canada led the way in North America, authorising same-sex marriage and adoptions in June 2005. ART and surrogacy are also allowed.
In the United States, with gay marriages still banned in 14 of the 50 states, a historic Supreme Court decision in June 2015 legalised gay marriage nationwide.
Mexico’s federal capital led the way in Latin America towards civil unions in 2007 and full marriages in 2009.
Same sex marriages are also legal in Argentina, Uruguay, Brazil and Colombia.
A crime in Africa
On a continent where around 30 countries ban homosexuality, only in South Africa can gays legally marry, adopt or have children by ART and surrogacy.
In Sudan, Somalia and Mauritania homosexuals face the death penalty, while only a handful of countries — Gabon, Ivory Coast, Chad, the Democratic Republic of Congo, Mali, and Mozambique — have decriminalised the practice.
Hostility in Middle East, Asia
Israel leads the Middle East in terms of respect for homosexual rights, and recognizes gay marriages performed elsewhere, though such marriages are not performed in Israel itself. Gay couples can jointly adopt children.
Homosexuality is theoretically punishable by death in Saudi Arabia and the United Arab Emirates, while Lebanon is more tolerant than other Arab countries.
In Asia, after Taiwan, the taboo surrounding homosexuality is slowly eroding in Vietnam and Nepal.
The only country in the region that allows gays to marry is New Zealand, which passed a law in April 2013, 27 years after homosexuality was decriminalised.
The most recent attempt to legalise gay marriage in Australia hinged on a planned referendum that was blocked in November 2016.