  We present results concerning a lattice study of the electroweak
$\rho$-parameter. We have used an SU(2)$\times$U(1) symmetric chiral Yukawa
model built with Zaragoza fermions. The decoupling of the species doublers in
this model is verified numerically. We find that the numerical data for
$\Delta\rho$ are well described by one-loop perturbation theory with the same
finite volume and with the same finite cut-off. However, a finite cut-off can
cause substantial deviations of $\Delta\rho$ from the standard value, even in
infinite volume.
