After I finished Dawn I knew I had to continue the trilogy. The world that Butler built in for this story is full of complicated, rich characters, both human an alien. Xenogenesis explores the union or fusion of these two groups through the main character Akin, the first human-Oankali male construct. Butler continues to explore human nature, a contradiction in itself, this time seen from the eyes of someone that is not fully human, nor fully alien.
Butler touches so many subject in such a swift, seamless manner that you don't realize you are thinking about social issues until you put the book (or headphones in my case) down and have this feeling of "wow"
Lillith takes a secondary role in this installment; as I mentioned it is Akin who takes center stage trying to merge the two points of view: a very guttural, visceral one coming from his human side and partners, and a more logical, cold one from this Oankali side. He represents, to me at least, the struggles a lot of immigrant kids have during their life time, Of course, Akin's struggle and his definitions will affect the future of what is left from humanity and the future of the trade.
Racism is also a constant subject so far in this trilogy; while Dawn dealt a bit more with sexism, in this case I felt this point was left aside, but not ignored. The rage against Lillith, the prejudices against her and whatever might come through her is still present, not only with those who actually met her, but her "legend" has grown, to a point that there is even talk of her being possessed. That said most of the women present in the rebel camps are delegated to secondary roles all the time and most of the men turn to "macho" behavior.
Seeing Akin grow, not only physically but in his mind was so interesting. The approach of him being a teenager in both communities puts him in multiple situations where he was feeling frustrated and has to learn not only to be an adult but to express as one and be able to share and convince his piers of the changes he is bringing.
I think that doing this trilogy in audio has given me the opportunity to identify the different Oankalis better and to sort of pin point their personalities; I've read several reviews mentioning that it is hard to differentiate between them.
From a biologist point of view I think the concept of trade, the way the Oankali see it, is fascinating. The concept is mostly explained on the first book, but is always present during Adulthood Rites.
I would totally recommend this series so far to anyone who loves SciFi and society construction.