  $f(R)$-theories of gravity are reviewed in the context of the so called
gravitational baryogenesis. The latter is a mechanism for generating the baryon
asymmetry in the Universe, and relies on the coupling between the Ricci scalar
curvature $R$ and the baryon current. Gravity Lagrangians of the form ${\cal
L}(R)\sim R^n$, where $n$ differs from 1 (the case of the General Relativity)
only for tiny deviations of a few percent, are consistent with the current
bounds on the observed baryon asymmetry.
