I’m not in a position to comment on the validity of the science and conclusions presented and don’t care enough to actively seek out the book written to refute them. I will, however, say that the vast majority of what’s presented here is irrelevant either way. The book itself states at one point that “natural” human behavior can change greatly when the conditions do without this making it any less natural, so the behavior patterns of immediate-return hunter-gatherers, not to mention bonobos, need not have anything to do with those of the tremendous majority of people since the advent of “civilization”.
What is relevant has to do with what would be right and making use of the uniquely human capacity of using reason to analyze instincts and urges and override them if that proves the better course of action. One major issue would be commitment, maintaining relationships, be they exclusive or not, yet the authors infuriatingly tend to use the data to argue against it, at least until the last part. But for me personally, as a militant antinatalist and with overpopulation as my main cause, the biggest problem is how many arguments, be they for the current socially-acceptable model or for that the authors advocate, rely on having and raising children at a time when behaviors based on or leading to that need to be stamped out by any means necessary.
Still, the book is written reasonably well, reads easily enough and even the first four parts may be mildly interesting in themselves. But anyone caring for what may actually be relevant in the present day may skip straight to the last part, or perhaps even the last chapter, where the authors seem to plead their case more directly and open up a conversation about what clearly doesn’t work in the current model, the suffering caused by the breakups inherent to serial monogamy and the unhappiness caused by enforced exclusivity with one partner and perhaps limited intimacy with other people. That is indeed what we need to find solutions for, whether they match or run counter to our “nature”.