  In light of recent experimental results, we present updated bounds on the
lightest Higgs boson mass in the Standard Model (SM) and in the Minimal
Supersymmetric extension of the Standard Model (MSSM). The vacuum stability
lower bound on the pure SM Higgs boson mass when the SM is taken to be valid up
to the Planck scale lies above the MSSM lightest Higgs boson mass upper bound
for a large amount of SUSY parameter space. If the lightest Higgs boson is
detected with a mass M_{H} < 134 GeV (150 GeV) for a top quark mass M_{top} =
172 GeV (179 GeV), it may indicate the existence of a fourth generation of
fermions. The region of inconsistency is removed and the MSSM is salvagable for
such values of M_{H} if one postulates the existence of a fourth generation of
leptons and quarks with isodoublet degenerate masses M_{L} and M_{Q} such that
60 GeV < M_{L} < 110 GeV and M_{Q} > 170 GeV.
