We present a phenomenological theory of randomly cross-linked polymer networks based on the separation of solid-like and liquid-like degrees of freedom and taking into account the frozen inhomogeneity of network structure. The complete solution of the statistical mechanics of this model is given, and the monomer density correlation functions are calculated for neutral gels in good and Theta solvents. The theoretical scattering curves are compared to the results of small angle neutron scattering and light : scattering experiments, and new experimental tests of our theory are proposed.