  Based on a study of {\it charge,} (C), {\it parity} (P) and {\it time
reversal} (T) symmetries we show how a CP violating network of defects in the
early Universe may bias baryon number production. A static network, even though
it violates CP, respects CPT and hence does not bias baryon number production.
On the other hand, the {\it ordering dynamics\/} of defects in a network,
governed by the interplay of string tension, friction, inertia and the
expansion of the Universe, results in the dynamical breakdown of CPT symmetry
and may lead to a net baryon number production.
