  We argue that Left-Right parity symmetry $\mathcal{P}$ can arise as a
discrete remnant of a unified gauge symmetry. The high-energy unification
necessarily includes the gauging of the Lorentz symmetry, bringing into the
game gravitational interactions, and leading to a gravi-GUT scheme. Parity
emerges unbroken below the Planck scale, and can be broken spontaneously at
lower energies making contact with the Standard Model. This framework motivates
the spontaneous origin of parity violation as in Left-Right symmetric theories
with $\mathcal{P}$. The possible unifying gauge groups are identified as
SO(1,7) for gravitational and weak interactions, or SO(7,7) for a complete
unification.
