  Electroweak baryogenesis provides a very attractive scenario to explain the
origin of the baryon asymmetry. The mechanism of electroweak baryogenesis makes
use of the baryon number anomaly and relies on physics that can be tested
experimentally. It is today understood that, if the Higgs mass is not larger
than 120 GeV, this mechanism may be effective within supersymmetric extensions
of the Standard Model. In this work, we reconsider the question of baryon
number generation at the electroweak phase transition within the context of the
minimal supersymmetric extension of the Standard Model. We derive the relevant
diffusion equations, give a consistent definition of the sources, and compare
our results with those appearing in the recent literature on this subject
