I discuss the importance of CP violation (CPV) in cosmology and give
some common arguments why it is believed that the CPV of the Standard
Model cannot be sufficient to explain the observed baryon
asymmetry. Then I go on to argue why these arguments might fail in
an effective approach where the quarks have been integrated out. I
discuss in detail how to obtain the corresponding bosonic effective
theory by using the worldline formalism with special emphasis on
CP-violating operators. Finally I comment on the use of this effective
theory in baryogenesis calculations.