Is torsion needed in a theory of gravity? A reappraisal
  It is known that General Relativity ({\bf GR}) uses a Lorentzian Manifold $(M_4;g)$ as a geometrical model of the physical spacetime. The metric $g$ is required to satisfy Einstein's equations. Since the 1960s many authors have tried to generalize this model by introducing torsion. In this paper we discuss the present status of torsion in a theory of gravity. Our conclusion is that the general-relativistic model of the physical spacetime is sufficient for the all physical applications and it seems to be the best satisfactory. 
Janusz Garecki (Institute of Mathematics, University of Szczecin,   Szczecin, Poland, EU)
gr-qc