  We use sampling techniques to find robust constraints on the masses of a
possible fourth sequential fermion generation from electroweak oblique
variables. We find that in the case of a light (115 GeV) Higgs from a single
electroweak symmetry breaking doublet, inverted mass hierarchies are possible
for both quarks and leptons, but a mass splitting more than M(W) in the quark
sector is unlikely. We also find constraints in the case of a heavy (600 GeV)
Higgs in a single doublet model. As recent data from the Large Hadron Collider
hints at the existence of a resonance at 124.5 GeV and a single Higgs doublet
at that mass is inconsistent with a fourth fermion generation, we examine a
type II two Higgs doublet model. In this model, there are ranges of parameter
space where the Higgs sector can potentially counteract the effects of the
fourth generation. Even so, we find that such scenarios produce qualitatively
similar fermion mass distributions.
