  We quantitatively study the charge transport mechanism of electroweak
baryogenesis in a realistic two-Higgs-doublet model, comparing the
contributions from quarks and leptons reflecting from electroweak domain walls,
and comparing the exact profile of the CP-violating phase with a commonly used
ansatz. We note that the phenomenon of spontaneous CP violation at high
temperature can occur in this model, even when there is no CP violation at zero
temperature. We include all known effects which are likely to influence the
baryon production rate, including strong sphalerons, the nontrivial dispersion
relations of the quasiparticles in the plasma, and Debye screening of gauged
charges. We confirm the claim of Joyce, Prokopec and Turok that the reflection
of tau leptons from the wall gives the dominant effect. We conclude that this
mechanism is marginally strong enough to produce the observed baryon asymmetry
of the universe.
