"Mature" Genres and Genre Ages

In the "Yummy" review, Todd says that R&B is "the most adult of genres" and that he's criticized a lot of R&B songs that come off as too immature because of it. I agree with him mostly for a few reasons, one of course being the overt sexuality and sensuality of a lot of R&B, but also the emotional maturity that you find in a lot of great R&B songs, including some that Todd has liked recently like "On My Mama" by Victoria Monét and "Good Good" by Usher. This isn't to say that every song in the genre is mature, though, given that "Yummy" itself is technically an R&B song with perhaps the most childish word (outside of actual toddler babble-words like binky or ba-ba) as the title.

With that in mind, though, what are the "ages" of other genres? I'd start with saying that punk generally sounds pretty young, teenager/young adult-ish, or it does at its best.