* Sweden, Norway, Spain most in favor of gay union
* Opposition highest in Japan, Hungary
By Patricia Reaney
NEW YORK, June 18 (Reuters) - Most adults in developed countries favor gay marriage or some type of legal recognition for same-sex couples and think they should be able to adopt children, according to an international poll released on Tuesday.
With the U.S. Supreme Court poised to rule on gay marriage this month and France's recent decision to legalize same-sex unions, an Ipsos poll for Reuters showed that 52 percent of people in 16 nations favor full marriage equality for gays and 21 percent support legal recognition but not marriage.
Only 14 percent of the 12,484 adults questioned in the survey objected to same-sex marriage, or any type of legal recognition, and 13 percent were unsure how they felt.
"What we see is that in every one of the 16 countries we surveyed, there is a majority in favor of allowing same sex couples to have some sort of legal recognition," said Nicolas Boyon, an Ipsos senior vice president.
"In nine out of 16 countries we see an outright majority in favor of full marriage equality," he added.
Nearly 60 percent of people polled thought gay couples should have the same rights as heterosexuals to adopt children and 64 percent thought same-sex couples were just as likely to raise children successfully.
"We see majorities in 12 of 16 countries supportive of gay parenting," said Boyon.
In Sweden, Norway, Spain, Belgium, Canada and France, where gay marriage is legal, a majority of people supported full equality for same-sex couples, along with most Germans, Britons and Australians.
In Argentina, which recognizes gay marriage, less than half of people (48 percent) favored marriage equality for gays.
The numbers were similar in the United States, where legal recognition of gay couples varies by state, with 42 percent supporting marriage for gays and 23 percent favoring legal recognition.
CHANGING ATTITUDES, SOCIAL MEDIA, RELIGION
Opposition to legal recognition or marriage of gays was highest in Hungary, South Korea, Poland and Japan, where 37 percent of people said they were unsure about how they felt.
"What is common to Hungary, South Korea and Poland is that by and large they are the countries that have the lowest percentage of people who report having a relative, a colleague, or a friend who is gay, lesbian, bisexual or transgender," said Boyon.
Three out of 10 people questioned said their attitude towards gay marriage had changed in the past five years, although they did not say how. Support for same-sex unions was highest among adults who had a relative, friend or colleague who is gay, lesbian, bisexual or transgender (LGBT).
Nearly 46 percent of people said they know someone who is LGBT. In Spain and Norway the number rose to 65 percent. But in South Korea and Japan the number dropped to 3 percent and 5 percent respectively.
"Either there is no exposure or there is just too much embarrassment to admit it," said Boyon. "It is likely there is still a stigma attached to the issue in those countries."
Social media and religion also had an impact on attitudes about gay marriage. People who are active on social media were more likely to support same-sex couples than those who were not online as much, according to the poll.
Twenty-seven percent of people who identify themselves with a religion were more likely to support some form of legal status for gay couples, the poll showed, while 17 preferred no recognition.
"Poland has the most opposition to adoption to same-sex couples and it is probably one of the most religious countries in the survey," Boyon said.
Ipsos questioned about 1,000 people in each country in the online survey except in Argentina, Hungary, Norway, Poland, South Korea and Sweden, where 500 residents were questioned.
The poll of 1,000 people has a margin of error of plus or minus 3.5 percentage points while one of 500 has a margin of 5 percentage points. (Editing by Doina Chiacu)