Interesting premise, but one that goes completely off the rails in the second half of the book. I liked the sheer difference it made to a human for that human to be raised by Martians, and it's a worthwhile thought experiment to explore nature versus nurture with a culture that is truly alien. The whole semi-religious place the story went to, however, held very little interest for me, and I was constantly put off by the oily, patronising tone of the book. (Especially when it came to women. I don't know how many infantilising nicknames Jill, in particular, was given over the course of this book, but my eyes started rolling early and didn't stop.) And for all Heinlein's obsession with free love, I note he was still pretty desperate to keep homosexuality out of this so it's nowhere near as shocking as I imagine he thought it was. I don't know, perhaps it's that I've read the extended version. This has 60,000 words that were cut from the original publication, which I haven't read and frankly will not bother with, but all I know is that this version dribbled on and on and on, and I'm mostly glad to be done with it while simultaneously feeling a bit sorry that the whole didn't live up to the premise.