  If cosmic ray protons interact with gas at roughly the mean density of the
interstellar medium in starburst galaxies, then pion decay in starbursts is
likely to contribute significantly to the diffuse extra-galactic background in
both gamma-rays and high energy neutrinos. We describe the assumptions that
lead to this conclusion and clarify the difference between our estimates and
those of Stecker (2006). Detection of a single starburst by GLAST would confirm
the significant contribution of starburst galaxies to the extra-galactic
neutrino and gamma-ray backgrounds.
