We have investigated the question of heterogeneity in gels using Brillouin scattering, depolarized Rayleigh scattering and dynamic light scattering measurements on methylmethacrylate (MMA) gels crosslinked with varying amount of ethylene-dimethacrylate (EDMA). We find that the k dependence of the phase velocity changes on increasing the cross-link content. For higher concentrations of crosslink we observe maxima and minima in the k dependence of the phase velocity which e associate with spatial inhomogeneities in the gel, with the formation of regions of low and high cross-link density, respectively. This micro-phase separation occurs around crosslink content of 3-4 %. At this same concentration depolarized Rayleigh measurements show a marked decrease in the number of MMA side groups capable of rotating.