Symmetry breaking, phase transition and gravity

We discuss some recent work in which the non-minimal coupling of gravity with a self-interacting scalar field in the presence of matter can lead to a phase transition when the sign of gravitational interaction changes. It is found that gravity becomes repulsive above a critical temperature which may lie in the range $10^{24}$ to $10^{32}K$ which obtains in the very early universe $(10^{-35} to 10^{-43} sec)$ of the standard model. The results are intimately connected with big bang and possible removal of singularity