  We briefly review the issues of proton decay and fermion masses and mixings
in minimal supersymmetric grand unified theories. We argue that minimal SU(5),
although tightly constrained by proton decay data, is still not ruled out.
However, we outline the advantages of SO(10) unification, in particular in the
model with renormalizable see-saw mechanism and its remarkable predictions of
(a) exact R-parity at low energies, (b) large atmospheric neutrino angle as a
consequence of b-tau unification and (c) 1-3 leptonic mixing angle close to its
upper limit.
