I'm surprised at how focused on sex these last 2 books have become. There's certainly nothing outrageous about it; it's just a bit unexpected. Yet these books aren't just sci-fi, or even speculative sci-fi: they are very much speculative anthropology as well. A large part of the study of any (human) culture would be sexuality/reproductive norms.

But, honestly, I should have been able to see this coming after, in the first book, we find out that Daneel, a humaniform robot, is very, precisely humaniform.