2015 — Luxembourg, Ireland, United States of America
2017 — Finland (the law is voted and signed but not yet in effect)
> I mean, Massachusetts legalized gay marriage in, what, 2003?
It's a good point but not without issues to wit the possibility of discontinuation or invalidation (California, Australian Capital Territory) and the fact that subdivision-level generally lacks many (or even most) of the protections and advantages normally granted (not to mention commonly a complete loss of recognition and attendant rights on moving outside the sub-territory)
Not to mention the population of the US is almost larger than every other country on that list combined.
It's an astounding feat to have accomplished such a vast cultural change in such a short amount of time. I've read recently that upwards of 25% of the entire US population has shifted its view on gay marriage in just ten years.
GP did specify "the developed world". It is a very fuzzy criteria, but however you slice it it's a far cry from 195 countries. The IMF identifies 37 advanced economies and the World Bank lists 31 "high-income OECD members" and 28 Development Assistance Committee members.
Coming from a European, I think that's a bit of unnecessary quibbling intended to justify condescending to the Americans. The United States started out as something like the European Union: a partial union of sovereign countries. As such, the appropriate comparison would be to ask: where's the ruling by the European Court of Human Rights declaring that all EU members must implement gay marriage, or else? Get with the times, you backwards-looking conservatives on the Old Continent!
And, to this day, the separate regions, which are admittedly larger than states, actually do behave somewhat like different countries. The differences become especially visible when you look at public policies and development indices: different states in the USA have various levels of honesty in government, civil rights, economic development, average education, etc. In fact, on a state-by-state basis, some US states are more highly developed than many/most European countries.
Note that those dates are somewhat oversimplifying things. For example, in Sweden there was something called "same-sex partnerships" from 1995 which legally was equivalent to marriage.
It was equivalent to marriage in Sweden which is an important difference, civil partnerships are inconsistent[0] and not necessarily transferrable across borders.
You're right that just listing the dates for same-sex marriage doesn't tell the whole picture, but adding civil partnerships and their details would necessarily expand the comment to something closer to a book.
[0] for instance in France civil unions are quite literally a marriage lite, open to all and very commonly used as a legally recognised engagement by heterosexual couples (>90% of civil unions are heterosexual)
> not to mention commonly a complete loss of recognition and attendant rights on moving outside the sub-territory
That wasn't necessarily the case; a bunch of Full-Faith-and-Credit-Clause cases were also being litigated before this decision. Though it would probably have ended up as more of a complex mess.
What fraction of the developed world had gay marriage, at what time, such that this statement makes sense?
I mean, Massachusetts legalized gay marriage in, what, 2003?