  The understanding of the physical processes that lead to the origin of matter
in the early Universe, creating both an excess of matter over anti-matter that
survived until the present and a dark matter component, is one of the most
fascinating challenges in modern science. The problem cannot be addressed
within our current description of fundamental physics and, therefore, it
currently provides a very strong evidence of new physics. Solutions can either
reside in a modification of the standard model of elementary particle physics
or in a modification of the way we describe gravity, based on general
relativity, or at the interface of both. We will mainly discuss the first class
of solutions. Traditionally, models that separately explain either the
matter-antimatter asymmetry of the Universe or dark matter have been proposed.
However, in the last years there has also been an accreted interest and intense
activity on scenarios able to provide a unified picture of the origin of matter
in the early universe. In this review we discuss some of the main ideas
emphasising primarily those models that have more chances to be experimentally
tested during next years. Moreover, after a general discussion, we will focus
on extensions of the standard model that can also address neutrino masses and
mixing, since this is currently the only evidence of physics beyond the
standard model coming directly from particle physics and it is, therefore,
reasonable they might also provide a solution to the problem of the origin of
matter in the universe.
