A novel interplay between d-wave superconducting order parameter symme
try and the underlying Cu 3d orbital based electronic structure of cop
per oxides leads to a striking anisotropy in the superfluid response o
f these systems. In clean tetragonal materials the c axis penetration
depth increases as T-5 at low temperature, in contrast to linear T beh
avior in the ab plane. Disorder is a relevant perturbation which cause
s all components of the superfluid response to depend quadratically on
temperature at low temperature. However, the crossover temperature sc
ale from the intrinsic d-wave behavior to the disorder dominated behav
ior for the in-plane response may be different from that for the out-p
lane response.