Gravitational Corrections to Fermion Masses in Grand Unified Theories
  We reconsider quantum gravitational threshold effects to the unification of fermion masses in Grand Unified Theories. We show that the running of the Planck mass can have a sizable effect on these thresholds which are thus much more important than naively expected. These corrections make any extrapolation from low energy measurements challenging. 
Xavier Calmet and Ting-Cheng Yang
hep-ph hep-th