As much as I am enjoying the book, it is not without flaws:
One flaw that wasn't apparent to me at the beginning of the book is that Mukherjee seems to present arguments to advance the narrative of the book, but doesn't acutally discuss the argument, or at least doesn't dicuss it directly and leaves it hanging until later in the book where he might discuss it but may or may not refer back to the argument.
In the last section I read, this annoyed me when he included two US legal decisions in his narrative: Roe v Wade and a case where a Mrs. Park sued a Dr. Chessin (to find the actual citation Park v. Chessin (1977) you have to dig very deep into the reference section, which aggravates me even more...).
The way that Mukherjee presents both cases (and one being more familiar to readers than the other) is limited to his narrative about genetics. He doesn't acknowledge the full legal argument for the decisions in both cases, and even when mentioning the argument of right to privacy in Roe v. Wade, this comes across as almost an aside to Mukherjee's tale of the story of genetic science.
The second case is treated similarly. He reports the outcome but the explanation is provided only through second-hand reporting and in one single sentence, which seems an unlikely thing to have happened in a case of such complexity and controversy.
In 1979, as opinions such as Joseph Dancis’s began to appear regularly in the medical and popular literature, the Parks sued Herbert Chessin, arguing that he had given them incorrect medical advice. Had the Parks known the true genetic susceptibilities of their child, they argued, they would have chosen not to conceive Laura. Their daughter was the victim of a flawed estimation of normalcy. Perhaps the most extraordinary feature of the case was the description of the harm. In traditional legal battles concerning medical error, the defendant (usually the physician) stood accused of the wrongful causation of death. The Parks argued that Chessin, their obstetrician, was guilty of the equal and opposite sin: “the wrongful causation of life.” In a landmark judgment, the court agreed with the Parks. “Potential parents have a right to choose not to have a child when it can be reasonably established that the child would be deformed,” the judge opined. One commentator noted, “The court asserted that the right of a child to be born free of [genetic] anomalies is a fundamental right.”
There are other flaws, too. References are not obvious, which makes it appear as if they are missing in large parts of the text. Good referencing is crucial to me in non-fiction books. Without an easy to follow reference system, the book looses credibility in my eyes or appears as sloppy research, neither of which I would want to accuse Mukherjee of because much of the book seems to be well thought out and seems to support that this work was put together diligently.
Another thing I have noticed is that some parts of his writing are stronger than others: well documented history of science seems to come across better than the discussion of thought experiments. And again, some discussion of complex consequences of the historical development and the impact on moral or ethical considerations seem to be left silent altogether.
Still, I'm enjoying the book and the chapters on the development of recombinant insulin and factor VIII (the blood-clotting agent used in the treatment of hemophilia) was riveting, even if large parts of that chapter read like the history of one specific pharmaceutical company.