  The asymmetry between matter and antimatter in the Universe indicates that
there was a period in the very early Universe when the CPT symmetry was broken.
The conservative interpretation is that the breaking was dynamical, induced by
the distinguished direction of time stemming from the cosmological expansion.
Here, I review the role which topological defect networks may play in
baryogenesis and how this relates to dynamical CPT symmetry breaking.
Particular attention is placed on defect-mediated electroweak baryogenesis. A
recent suggestion of defect-mediated QCD scale baryogenesis is also mentioned.
