The deuteron charge radius is calculated from the measurement of the Lamb shift in muonic deuterium, taking into account the electron vacuum polarization correction to the nuclear-structure effects. This correction is unexpectedly large and gives a mean-square charge-radii difference r_d^2-r_p^2 = 3.81747(346) fm^2 , which is now consistent with that obtained from the ordinary H-D isotope shift in the 1S-2S transition. This suggests that the long-standing discrepancy in the proton charge radius

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... obtained from electronic and muonic systems is due to an underestimated uncertainty in ordinary hydrogen spectroscopy.