Interesting, and I'm glad to hear any counterarguments (no idea who downvoted you). I'll have to read the book and/or studies before I could give a good reply, but judging from the Amazon reviews, it looks like even he mitigates it in the book by saying some parental actions can have important effects (for an extreme example, being violently abusive to your kids). Given stuff like that, and a lot of the recent stuff in social influence on epigenetics[1], I'm a bit skeptical where to draw the line between nature and nurture. But I'll really have to read the book and twin studies before I could debate those points.
[1] http://www.psmag.com/navigation/health-and-behavior/the-soci...