In two-proton pickup from 14C, the calculated cross-section ratio for the first two 0+ states of 12Be depends on the configuration mixing in these two states and on the amount of core excitation in the ground state (g.s.) of 14C. Using the 12Be wave functions that are reasonably well known, I have calculated this ratio as a function of the core excitation in 14C(g.s.). A measurement of this ratio should allow an independent determination of the 14C mixing—previously estimated to be about 12%.