  We show that a spinless theory of gravity is also allowed by the kinematics
of general relativity. In the absence of fermions the spinless theory of
gravity and the theories in the standard model of particle physics are the same
Yang-Mills theories with different gauge groups. Therefore, every theorem of a
pure Yang-Mills theory is valid for the spinless theory of gravity in vacuum,
i.e. it is unitary and renormalizable to all orders. When fermions are present
the spinless theory of gravity has an extra constraint due to the tetrad
postulate. A path integral quantization of this theory and all the Feynman
rules are presented.
