  Adding a second scalar doublet (eta^+,eta^0) and three neutral singlet
fermions N_{1,2,3} to the Standard Model of particle interactions with a new
Z_2 symmetry, it has been shown that eta^0_R or eta^0_I is a good dark-matter
candidate and seesaw neutrino masses are generated radiatively. A minimal
extension of this new idea is proposed to allow for its SU(5) completion.
Supersymmetric unification is then possible, and leptoquarks of a special kind
are predicted at the TeV scale.
