At first they built up to a short interview with a chimera. Karen Keegan from Boston one day found out she was a twin in one person. Part of her organs genetically were her sister's and part were hers. They blended into one functioning human during the earliest stages of pregnancy. That is a chimera.
The undertone in the last subject, and basically of the program is: is this right? One conclusion that stands out is: it could be dangerous considering we already have begun engineering while we still know so little in microbiology. But ethically? Even if we can make things work. We can cure disease, let microbes solve pollution and the energy problem? Is that right. Krulwich expresses it intuitively: it doesn't feel right, but other than that this question is not explored. It is as if they lack terms, or an entry into the philosophy.
In the past I have noted this inability apart from one podcast, the bioethics podcast, which knows it full well, but is so exclusively predisposed with its Christian fundamentalist outlook on the world, that it doesn't satisfy the need for a universal and not strictly evangelical answer.
More Radiolab:
War of the Worlds,
Wright Brothers,
Morality.
Bioethics:
Bioethics without Christ, please,
A useful map into Bio-Ethics,
Stem Cell Research: Science, Ethics, and Prospects.