An SO(10) GUT with see-saw masses for all fermions

We propose an SO(10) grand unified theory in which all fermions acquire see-saw masses. We include only two Higgs scalars, a 210-plet and a 16-plet. In addition to the regular fermions we include one singlet per generation, whose mass term breaks chiral symmetry, so that fermions can get masses. Required neutrino masses with large mixing as well as leptogenesis are possible in this model.