On the Renormalization of the S Parameter
  We calculate the S parameter of the standard model at one loop of fermions, using three different regularizations (dimensional, Pauli-Villars and lattice) and find an extra contribution to the S parameter besides the standard one for each case. This shows that the extra contribution recently reported for the lattice regularization is {\it not} necessarily tied to the non-decoupling effect of fermion doublers. We argue that the extra contribution should be subtracted in the renormalizable perturbative expansion. 
Sinya Aoki