I can tie these together. Even if the biologist is in favor of eugenics (selective breeding of humans) he probably also knows that we are not good judges of overall fitness. The econ guy may have some great ideas, but he knows the difference between theory and practice. In both cases they "know what they don't know". On a more personal level, maybe the biologist just wants to follow his heart (which is actually the correct move), and the economist likes to play it safe?

"You do you" is the correct answer in almost every case. Evolution does not pre-select and deliberately make copies. It's a process where individuals do their thing and let the chips fall where they may. The process takes care of the rest.