Jim Holt in the New York Times Magazine:
While there is much that is marvelous in nature, there is also much that is flawed, sloppy and downright bizarre. Some nonfunctional oddities, like the peacock’s tail or the human male’s nipples, might be attributed to a sense of whimsy on the part of the designer. Others just seem grossly inefficient. In mammals, for instance, the recurrent laryngeal nerve does not go directly from the cranium to the larynx, the way any competent engineer would have arranged it. Instead, it extends down the neck to the chest, loops around a lung ligament and then runs back up the neck to the larynx. In a giraffe, that means a 20-foot length of nerve where 1 foot would have done. If this is evidence of design, it would seem to be of the unintelligent variety.
Such disregard for economy can be found throughout the natural order. Perhaps 99 percent of the species that have existed have died out. Darwinism has no problem with this, because random variation will inevitably produce both fit and unfit individuals. But what sort of designer would have fashioned creatures so out of sync with their environments that they were doomed to extinction?
The gravest imperfections in nature, though, are moral ones. Consider how humans and other animals are intermittently tortured by pain throughout their lives, especially near the end. Our pain mechanism may have been designed to serve as a warning signal to protect our bodies from damage, but in the majority of diseases — cancer, for instance, or coronary thrombosis — the signal comes too late to do much good, and the horrible suffering that ensues is completely useless.
And why should the human reproductive system be so shoddily designed?