IN HER INTRODUCTION to Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts, science writer Emily Anthes tosses out a few examples of what genetically modified pets might look like one day. Imagine a cat that glows in the dark, she says—instant reading light! And forget remote-control cars—kids in the future might play with their very own remote-controlled rodent.

Anthes' tone is light, but the ideas seem designed to incite unease, even anger. Pets are products, as Anthes correctly notes, but once we've purchased them, they're family, and it's just downright discomfiting to think of someone tampering with a family member's genes. Sure, your English bulldog wouldn't exist if it weren't for humans meddling with the gene pool, but that's different than actually introducing foreign DNA into an animal's genome... right?

Anthes has set up this initial discomfort only to dismantle it, and she dials back the shock factor almost immediately. The first chapter of Frankenstein's Cat focuses on a genetically modified pet that's already on the market: GloFish carry a gene borrowed from jellyfish, causing them to light up under a black light. The fluorescent fish are sold in pet shops nationwide; they're an innocuous-enough seeming innovation, and Anthes offers their existence as a way to defuse the "yuck factor" of genetically modified animals.

"Maybe there are some people out there who went into pet stores expecting something monstrous and came away thinking that GloFish were not only harmless but actually downright cool," Anthes writes. "It's what can happen when we get the opportunity to have close, personal encounters with biotechnology."

Anthes' book explores a range of current and possible uses for transgenic animals (animals that have foreign DNA in their genome). The projects explored here are mind boggling, fascinating, and complex, from noble attempts to reduce diarrheal disease in children by feeding them genetically modified goat milk to a downright creepy project that turns insects into tiny flying cyborgs.

Anthes is clearly a proponent of thoughtful and well-regulated biotechnology, but she doesn't shrink from the ethical concerns inherent to the subject. Sure, there are readers for whom the very suggestion of genetically modified animals is anathema—who can't conceive of any reason to tamper with god and nature on the scale Anthes is describing. (There are also readers out there who think fluoride has no place in our drinking water.) For the rest of us, though, Frankenstein's Cat is a thorough and accessible starting point to a conversation that's only just getting started.