  Light stops can give a strong first order electroweak phase transition in the
Minimal Supersymmetric Standard Model (MSSM) satisfying one of the necessary
conditions for electroweak baryogenesis. I discuss the region of parameter
space where this occurs using a perturbative analysis of the Higgs effective
potential. Two-loop QCD corrections associated with stop loops are crucial to
open this baryogenesis window, which corresponds to 2.25 < tan beta < 3.6, one
stop not much heavier than the top quark, m_A > 120 GeV and a light Higgs boson
with m_h < 85 GeV. This region will be explored by LEP II very soon.
