Survival of the Sickest: A Medical Maverick Discovers Why We Need Disease

Moalem, a medical student with a Ph.D. in neurogenetics, asks a number of provocative questions, such as why debilitating hereditary diseases persist in humans and why we suffer from the consequences of aging. His approach to these questions is solidly rooted in evolutionary theory, and he capably demonstrates that each disease confers a selective advantage to individuals who carry either one or two alleles for inherited diseases. But very little is new; the principles, if not every particular, that Moalem addresses have been covered in Randolph Nesse and George Williams's Why We Get Sick , among others. Whether he is discussing hemochromatosis (a disorder that causes massive amounts of iron to accumulate in individuals), diabetes or sickle cell anemia, his conclusion is always the same: each condition offers enough positive evolutionary advantages to offset the negative consequences, and this message is repeated over and over. Additionally, Moalem's endless puns and simple jokes wear thin, but his light style makes for easy reading for readers new to this subject. (Feb.)