  In the context of the standard model the quantization of the electric charge
occurs only family by family. When we consider the three families together with
massless neutrinos the electric charge is not quantized any more. Here we show
that a chiral bilepton gauge model based on the gauge group SU(3)_C X SU(3)_L X
U(1)_N explains the quantization of the electric charge when we take into
account the three families of fermions. This result does not depend on the
neutrino masses. Charge quantization occurs either the neutrinos are massless
or Dirac or Majorana massive fields.
