Greg Egan is one of my favorite "hard science" SF authors, but in this one I felt he missed the mark. It wasn't until page 160 - half way in - that I finally figured out where he was trying to go, and even then he never tried to develop his hypothesis to its conclusions. Animals are mutating: Why? We learn "how" - the mechanics - but nothing of underlying causes, and the final conclusion seems like a cop-out.
Somehow it seems that only an Australian writer would have needed to set part of this novel in Toronto. Sure Egan was writing in 1999, but why would a guy in his late teens in Toronto of the 2020s have to worry about his guardianship of his younger sister just because he's gay? Maybe still in Oz, and maybe his age would still be a barrier in Toronto, but we got over the gay issue years ago.
An enjoyable story, but not up to the standard of Distress.