  A simple model to accomodate light sterile neutrinos naturally with large
mixing with the usual neutrinos has been proposed. The standard model gauge
group is extended to include an $SU(2)_S$ gauge symmetry. Heavy triplet higgs
scalars give small masses to the left-handed neutrinos, while a heavy doublet
higgs scalar give mixing with the sterile neutrinos of the same order of
magnitude. The neutrino mass matrix thus obtained can explain the solar
neutrino deficit, the atmospheric neutrino deficit, the LSND data and hot dark
matter. Lepton number is violated here through decays of the heavy triplet
higgs, which generates the lepton asymmetry of the universe, which in turn
generates a baryon asymmetry of the universe.
