Yeah, based on his examples I guess the original poster meant "superhero comics" when he said "comics". (I hate when people automatically assume "comics" mean supeheroes, by the way.) The first mass-produced pornographic comics (which obviously had sex scenes as well) were probably the Tijuana bibles
, which date back to as early as the 1920s. As for sex-scenes in non-pornographic comics, as far as I know, they started showing up in American underground comics, Japanese manga, and European art comics in the late 1960s, i.e. around the same time mainstream movies started having sex scenes as well.
But if were talking about sex scenes in mainstream superhero comics, I don't know when the first one happened. Most likely it didn't happen before the 1990s, because before that the main audience for superhero comics was preteen kids, or at least the superhero publishers thought that way. Though before the 1990s sex was implied, of course; you had scenes were a hero (or heroine) walks into his lover's apartment/bedroom/etc, and then the scene cuts to the next morning. But actual sex scenes with people lying naked in the bed weren't done back then.
edited 14th Apr '12 1:25:49 AM by Tuomas