  A study of the three-family local gauge group SU(3)_c X SU(3)_L X U(1)_X with
right-handed neutrinos is carried out. We use the minimal scalar sector able to
break the symmetry in a proper way and produce, at the same time, masses for
the fermion fields. We embed the structure into a simple gauge group and, by
using experimental results from the CERN LEP, SLAC linear collider and atomic
parity violation data, we also constraint relevant parameters for the new
neutral and charged currents. We discuss the mass spectrum for the gauge boson
sector and for the spin 1/2 particles. With the use of discrete symmetries and
the introduction of extra scalar fields, a consistent mass spectrum could be
constructed.
