  We analyze the quantum transport equations for supersymmetric electroweak
baryogenesis including previously neglected bottom and tau Yukawa interactions
and show that they imply the presence of a previously unrecognized dependence
of the cosmic baryon asymmetry on the spectrum of third generation quark and
lepton superpartners. For fixed values of the CP-violating phases in the
supersymmetric theory, the baryon asymmetry can vary in both magnitude and sign
as a result of the squark and slepton mass dependence. For light, right-handed
top and bottom quark superpartners, the baryon number creation can be driven
primarily by interactions involving third generation leptons and their
superpartners.
