  f(R)-theories of gravity are reviewed in the framework of the
matter-antimatter asymmetry in the Universe. The asymmetry is generated by the
gravitational coupling of heavy (Majorana) neutrinos with the Ricci scalar
curvature. In order that the mechanism works, a time varying non-zero Ricci
curvature is necessary. The latter is provided by f(R) cosmology, whose
Lagrangian density is of the form {\cal L}(R)\sim f(R). In particular we study
the cases f(R)\sim R+\alpha R^n and f(R)\sim R^{1+\epsilon}.
