  In models with the fundamental gravity scale in the TeV range, early
cosmology is quite different from the standard picture, because the universe
must have arisen at a much lower temperature and the electroweak symmetry was
probably never restored. In this context, baryogenesis appears to be
problematic: if the involved physics is essentially that of the Standard Model,
``conventional'' non-conserving baryon number processes are completely
negligible at such low temperatures. In this paper we show that the observed
matter-antimatter asymmetry of the universe may be generated by gravitational
decay of TeV-mass particles: such objects can be out of equilibrium after
inflation and, if their mass is of the same order of magnitude as the true
quantum gravity scale, they can quickly decay through a black hole intermediate
state, violating global symmetries, in particular, baryon number. In this
context, we take advantage of the fact that the ``Sakharov conditions'' for
baryogenesis can be more easily satisfied with a low fundamental scale of
gravity.
