  We consider the possibility of observing a parity violating but $CP$
conserving interaction in the symmetry breaking sector of the electroweak
theory. We find that the best probe for such an interaction is a
forward-backward asymmetry in $W^+W^-$ production from polarized $e^-_R e^+_L$
collisions. An observable asymmetry would be strong evidence against a
custodial $SU(2)$ symmetry. We also discuss the effects of such an interaction
in future $e^- \gamma$ colliders as well as in rare decays of $K$ and $B$
mesons.
