The cross sections for the p(e,e'${\mathrm{\ensuremath{\pi}}}^{+}$)n and d(e,e'${\mathrm{\ensuremath{\pi}}}^{+}$)2n reactions are calculated using a simple model with pion, nucleon and \ensuremath{\Delta}-resonance degrees of freedom, for the kinematical conditions used in a recent Saclay experiment. The final-state interactions between the two outgoing neutrons are found to have a large effect on the d(e,e'${\mathrm{\ensuremath{\pi}}}^{+}$)2n reaction. The calculated quenching of the ${\mathrm{\ensuremath{\pi}}}^{+}$ production cross section for deuterium is in agreement with that observed experimentally. It is predicted that, due to the strong final-state interaction in the singlet S state of the two neutrons, the e,e'${\mathrm{\ensuremath{\pi}}}^{+}$ cross-section can have a large dependence on the orientation of deuteron spin. In principle this dependence can be observed with tensor polarized deuterium targets under suitable kinematical conditions.