  If the Standard Model particle content is extended by gauge singlet fermions
(right-handed neutrinos), active neutrinos generically acquire (Majorana)
masses, in agreement with our current understanding of the lepton sector. If
the right-handed neutrino masses are of the same order as the electroweak
symmetry breaking scale, it is usually expected that these will not mediate any
experimentally observable effects. Here, I explore the fact that this is not
necessarily the case. If neutrino masses are "accidentally small",
active-sterile mixing angles can, according to current experimental bounds, be
as large as several percent. If this is the case, I argue that the dominant
decay mode of light (M_H less than 130 GeV) Higgs bosons could be into an
active and a sterile neutrino. The sterile neutrino decays promptly into a
charge lepton and an on- or off-shell W-boson, so that the dominant Higgs boson
decay mode is H to leptons + jets + missing transverse energy.
