The times, they are a changin'. As seen in my post about interracial marriage, attitudes about love are becoming more and more modern. And now, although gay marriage is definitely less of a norm than interracial marriage, attitudes are progressing in this modern era.
As seen in this infographic, attitudes have shifted dramatically in the past ten years. The majority attitude has shifted, in 2001 more people were in opposition to gay marriage and now in 2011 half to just barely more people are in favor of gay marriage. The shift alone is revolutionary!
Support varies by political party. As assumed, democrats were more supportive of gay marriage than republicans in 2001 and remain more supportive of gay marriage in 2011. Democrats and independents both increased support of gay marriage between these years, while republican support remained relatively the same.
Another interesting data point is the thoughts on gay couples raising children. While it isn't a drastic change, a larger percent of the population thinks that it will benefit society than before, and most people don't think it will make a difference. [Via]