  Gravitational lensing provides a strict test of cosmogonic models. Detailed
numerical propagation of light rays through a universe having a distribution of
inhomogeneities derived from the standard CDM (cold dark matter) scenario with
the aid of massive, fully nonlinear computer simulations is used to test the
model. It predicts that we should have seen far more widely split quasar images
than have been found. These and other inconsistencies rule out the COBE
normalized CDM model with $\Omega=1$ and $H_0=50$km/s/Mpc; but variants of this
model might be constructed, which could pass the stringent tests provided by
strong gravitational lensing.
