  Assuming that the leptons and quarks other than top are massless at tree
level, we show that their masses may be induced by loops involving the top
quark. As a result, the generic features of the fermion mass spectrum arise
from combinations of loop factors. Explicitly, we construct a renormalizable
model involving a few new particles, which leads to 1-loop bottom and tau
masses, a 2-loop charm mass, 3-loop muon and strange masses, and 4-loop masses
for first generation fermions. This realistic pattern of masses does not
require any symmetry to differentiate the three generations of fermions. The
new particles may produce observable effects in future experiments searching
for mu to e conversion in nuclei, rare meson decays, and other processes.
