  We investigate the quantum behaviour of sigma models on coset superspaces G/H
defined by Z_{2n} gradings of G. We find that, whenever G has vanishing Killing
form, there is a choice of WZ term which renders the model quantum conformal,
at least to one loop. The choice coincides with that for which the model is
known to be classically integrable. This generalizes results for models
associated to Z_4 gradings, including IIB superstrings in AdS_5\times S^5.
