From theoatmeal.com
The Gay Marriage Debate--Now and 50 Years From Now

What this cartoon is perhaps missing is how much the debate has already shifted in our lifetimes.
I think (although I'm somewhat out of my depth here) that in the 1950s and 1960s homosexuality was pretty much a non-issue.  With the Gay liberation movement in the late 60s and 70s, those of us growing up in the 1980s and 1990s were the first generation to get the full force of the conservative backlash against homosexuality.
I remember my youth pastor used to go on polemics against gay culture, and my Bible teacher in middle school used to actually say (repeatedly) that someday God would destroy California like he did Sodom and Gomorrah because of homosexuality.
Now the culture has moved on so that this kind of bigotry is increasingly on its way out.
I'd like to think that the culture has changed enough since that time that you couldn't get away with teaching that kind of stuff to kids anymore.  (Although I've lost touch with the Christian education system, so I don't really know for sure.  But I'd like to imagine they're a lot more on the defensive now than they were back in the 90s.)