  If the present baryon-asymmetry is due to a Planck or GUT-scale matter
asymmetry then baryon- or lepton-number violating processes are constrained by
the condition that they do not subsequently erase this asymmetry. We present a
revision of the analysis of sphaleron baryon-number violating processes in the
standard model including lepton-mass effects. We find the surprising result
that a GUT-scale matter-asymmetry can survive the $B$ and $L$ violating
sphaleron interactions even though ($B- L$) is conserved and equals zero for
all temperatures. We extend the analysis to cover the minimal supersymmetric
standard model (MSSM) and also derive the constraints on the R-parity violating
couplings in extensions of the MSSM. In the case of the baryon number violating
dimension 4 operators we find, contrary to current wisdom, that the resulting
bounds can be avoided completely because of a residual lepton-flavour number
conservation; in the case of lepton number violating operators we find the
bounds are flavour dependent and can be avoided completely in definite flavour
channels. We also consider how the bounds are modified in the case there is a
Grand Unified extension of the supersymmetric model which introduces new lepton
flavour violating couplings.
