  An alternative to the famous see-saw mechanism is proposed to explain the
smallness of the neutrino masses (if present). This model involves a fourth
family which mixes very little with the other three. It contains one heavy
neutrino (mN > mZ /2) and three very light neutrinos whose masses are
radiatively induced. In contrast with the see-saw mechanism, all neutrino
masses are Dirac masses. In one particular scenario, the three light neutrinos
are almost degenerate in mass and are found to be consistent with fits to the
Solar and Atmospheric neutrino deficits. They might even account for the Hot
Dark Matter.
