  The Bethe-Salpeter equation for the T-Matrix of D-D* scattering is solved
with a meson-meson potential that results from 2nd order Born approximation of
quark exchange processes. This potential turns out to be complex and energy
dependent due to the pole contribution from the coupling to the intermediate
J/psi-rho meson pair propagator. As a consequence, a bound state with a mass
close to 3.872 GeV occurs in the J/psi-rho continuum. This result suggests that
quark exchange forces may provide the solution to the puzzling question for the
origin of the interaction which leads to a binding of D and D* mesons in the
X(3872) state.
