Sep 27 2021 08:00 AMGENEVA - Nearly two-thirds of Swiss voters backed the introduction of same-sex marriage in a referendum held Sunday, with campaigners calling it a historic moment for gay rights in Switzerland.The government's plans to introduce "marriage for all" were challenged by opponents, who successfully triggered a referendum.But some 64.1 percent of voters in the wealthy Alpine nation supported the move, on a 52 percent turnout."It is a historic day for Switzerland, a historic day when it comes to equality for same-sex couples, and it is also an important day for the whole LGBT community," said Jan Muller of the "yes" campaign committee.Switzerland is the world's 30th country to adopt same-sex marriages, and was one of the last.