  The first order contribution to frictional drag in bi-layered fermion gas is
examined. We discuss the relevance of single photon exchange in the evaluation
of transresistance, which is usually explained by second order effects such as
Coulomb and phonon drag. Since the effective e.m. interaction is unscreened, in
the d.c. limit we obtain a finite (and large) contribution to
transconductivity.
