Book excerpt: When deformed frogs-many with missing legs or eyes, footless stumps, or misshapen jaws-began to emerge from Minnesota wetlands, alarm bells went off. What caused such deformities? Pollution? Ultraviolet rays? Biological agents? And could the mysterious cause also pose a threat to humans? Former government biologist Judy Helgen provides an inside view of a highly charged environmental issue that continues to spark controversy among scientists, politicians, and government agencies. Book jacket.