The storyboard artist, Rodney Clouden, won an Emmy in 2001 for "Individual Achievement in Animation".
Fry was apparently sterilized earlier by the F-Ray The worms fix his sperm problems.
The title is a parody of Milton's famous poem, "Paradise Lost."
This episode is similar to the 1966 movie Fantastic Voyage.
The worms seem to not only have re-fertilized fry, but also made his sperm much larger and stronger than a normal sperm as when comparing the characters to other body parts and the sperm Zoidberg rode on, it's comically oversized.
The title of the episode implies that the worms are parasites. In truth, they are a mutualistic species (not to be confused with symbiotic species, which could mean either parasitism or mutualism), meaning that they in fact improve their host and benefit off of the same gain that the infected does.
ScienceDaily (Mar. 23, 2011) Researchers at McMaster University discovered that the "cross-talk" between bacteria in our gut and our brain plays an important role in the development of psychiatric illness, intestinal diseases and probably other health problems as well including obesity.Jane Foster, associate professor in the Department of Psychiatry and Behavioural Neurosciences of the Michael G. DeGroote School of Medicine,says that research shows gut bacteria influences how the brain is wired for learning and memory.