On the other hand, the evolution of pathogens drives them to get around defenses and hijack the functions of host cells. If you’re looking to alter the function of cells, then pathogens seem like a good place to start.

The Viagra example is pretty funny too — it turns out that it’s proportionally harder (ahem) to get an erection the more the woman differs from being 20, thin, and beautiful. Don’t worry — we’ve got a drug for that.