  We explore the possible implications that new families, that are being
searched for at the LHC, would have on neutrino masses. In particular, we have
explored the possibility that the smallness of the observed neutrino masses is
naturally understood in a modified version of the Standard Model (SM) with
complete extra generations of fermions, i.e., that have right-handed neutrinos,
in which neutrino masses are generated at two loops. With one extra family it
is not possible to fit the observed spectrum of masses and mixings. However,
the radiative mass generated provides an important constraint in these kind of
models, so the neutrino masses do not exceed their cosmological bound. Within
the context of two extra families, we analyse the allowed parameter space and
the possible phenomenological signals. Contribution to NUFACT 11, XIIIth
International Workshop on Neutrino Factories, Super beams and Beta beams, 1-6
August 2011, CERN and University of Geneva (Submitted to IOP conference
series).
