  The Higgs sector of the Standard Model with one right-handed neutrino per
family is systematically analyzed. In a model with intergenerational
independent mixings between families, we can account for very light neutrinos
acquiring Majorana masses radiatively at the first electroweak loop level. We
also find that in such a scenario the Higgs coupling to the light-heavy
neutrinos and to the heavy-heavy ones may be remarkably enhanced with
significant implications for the production of these heavy neutrinos at high
energy colliders.
