Books: Neither nature nor nurture, argues controversial author Paul Ehrlich.
PS RATING: B-
Chang and Eng, the first documented Siamese twins, shared a body and all its genes. They were raised in an identical environment, yet their personalities differed to extremes that sometimes led them to haul off and punch each other. One was passive and sober, the other aggressive and drunk. Now, more than a century after their death, their story illustrates the still-growing debate over what determines who we are: our biology, our environment, or both.