I think, while it’s relatively clean as far as sex or violence goes, there’s some problematic elements that speak to the author’s “old fashionedness”. For one, the author seems to think that being possessive of a romantic partner to the point of violence is a heroic trait. On multiple occasions otherwise sympathetic characters clench their teeth or their fists at or even attack other male characters that show interest in their female partners. There’s also a a kind of conspicuous lack of queer characters. He does have a Bob finally identify as a “Bobby”, but it takes hundreds of generations and they’re used to illustrate just how much the iterations are drifting from the original, not to mention that they never actually show up in the books (yet). Every Bob is heterosexual. I don’t recall any gay or queer characters ever being mentioned in any of the books.

There’s also a suspicious undercurrent of genetic determinism. On multiple occasions characters are encountered with a very heavy implication that they are just born better and smarter and superior to their peers, and I find that kind of thought smells off to me. It reminds me too much of eugenics and people who believe in a master race or that certain classes are born to rule others.

They are fun reads and certainly enjoyable. As far as having teens read them, I would be concerned that they would absorb everything without being critical enough of the content. I think there are better, more inclusive choices that are more modern in their attitudes and cast of characters.