{rho} Polarization and Model Independent Extraction of |V{sub ub}|/|V{sub cd}| from D--> {rho}{ell}{nu}and B--> {rho}{ell}{nu}

We briefly discuss the predictions of the heavy quark effective theory for the semileptonic decays of a heavy pseudoscalar to a light one, or to a light vector meson. We point out that measurement of combinations of differential helicity decay rates at Cleo-c and the B factories can provide a model independent means of extracting the ratio |V{sub ub}|/|V{sub cd}|. We briefly discuss the corrections to this prediction.