  We study the impact of the positivity of the measure of CP violation in
neutrino oscillations on the values of |V_e3| and |V_mu1|. We use the available
information on the solar and atmospheric mixing parameters |V_e2| and |V_mu3|
provided by neutrino oscillation data. We conclude that large values of |V_e3|
are preferred at 95% confidence level. This, in turn, favours large values for
J_lepton compared to CP violation in the quark sector.
