Alarming. Maybe. Full disclosure up front: I'm not overly concerned about human extinction. But for those that might be concerned that it might be possible... you're probably going to want to read this book. Swan has spent a lifetime studying human reproduction, and the data she presents here is genuinely startling. I fully admit I am no expert here, but her case is well documented, sometimes with pages of footnotes at the end of each chapter and with a bibliography roughly 1/3 the total page count of the book. Which is average ish for a well-documented science book in my experience. Really the only quibbles I have with the book at all truly are completely philosophical. As I said, I'm not actually concerned about human extinction, and in the final chapter before her conclusion, Swan calls for a number of government actions... and I'm an avowed anarchist. ;) That said, this text is a very clear example of the need for leaders - and even individuals - to listen to subsystem experts (in thie case, human reproduction) but be aware of how recommendations from those experts about their subsystems could lead to disastrous results in other areas, and work to address the concerns of the experts while avoiding the outside disastrous outcomes. Still, for the hard science that the bulk of the text shows here, this is truly an excellent read. Very much recommended.