  In the presence of ${\bf 126 + \bar{126}}$ Higgs multiplets in a SO(10)
theory, the fermion masses get contributions from an induced vacuum expectation
value (VEV) of a $SU(2)_L$ doublet residing in ${\bf 126}$ which differentiates
between quarks and leptons by a relative sign leading to a significant
correction to the prediction of the mass ratio of the bottom quark and the tau
lepton for ranges of the mass of this extra doublet. We perform a two-loop
renormalization group analysis of the minimal version of the one-step
supersymmetric SO(10) model to display this and re-calculate the corrections to
the top quark mass in the presence of such an induced VEV. We show that these
effects make the infra-red fixed point scenario consistent with experimental
results.
