  Scales of mass generation for Majorana neutrinos (as well as quarks and
leptons) can be probed from high energy 2 --> n inelastic scattering involving
a multiple longitudinal gauge boson final state. We demonstrate that the
unitarity of 2 --> n scattering puts the strongest new upper limit on the scale
of fermion mass generation, independent of the electroweak symmetry breaking
scale $v=(\sqrt{2}G_F)^{-1/2}$. Strikingly, for Majorana neutrinos (quarks and
leptons), we find that the strongest 2 --> n limits fall in a narrow range,
136-170 TeV (3-107 TeV) with n=20-24 (n=2-12), depending on the observed
fermion masses. Physical implications are discussed.
