  It is usually assumed that the proton stability requires the coloured triplet
partner of the electroweak Higgs doublet to be superheavy (with a mass $\sim
M_{GUT}$). We show that this is a very model-dependent statement and the colour
triplet can be as light as the weak doublet without leading to the proton decay
problem: instead of using the mass difference the splitting can occur between
the doublet and triplet Yukawa coupling constants. In this scenario the GUT
symmetry breaking automatically induces an extremely strong suppression $\sim
M_W/M_{GUT}$ of the coloured Higgs effective Yukawa coupling; this happens
without any fine--tuning, just because of the Clebsch factors. Conceptual
differences of the above picture are: (1) an essentially stable proton: both $d
= 5$ and $d = 6$ proton decay mediating operators are suppressed by the same
factors $\sim (M_w/M_{GUT})^2$; (2) the possibility of solving the $\mu$
problem by the light gauge singlet field (this fact would lead to the
destabilization of the hierarchy in the standard case); (3) the existence of
the long--lived, light, coloured and charged supermultiplet in the 100 GeV mass
region. We construct two explicit SO(10) examples with the above properties,
with superpotentials most general under the symmetries.
