According to The Guardian:
The senior author of a study claiming to find that a brief, face-to-face conversation with a gay political canvasser had the ability to soften the opinions of those opposed to same-sex marriage has retracted its findings, claiming there were errors in his co-author’s work.
The study, which was published in Science in December and was widely covered in the media, found support for same-sex marriage climbed among voters who had a single conversation with a gay or lesbian canvasser. In addition, the authors found that the changed views not only lasted for at least a year, but also positively influenced the opinions of other members of the household.
The optimistic slant on human nature provided by the research evaporated this week, however, when Professor Donald Green retracted the paper.