  A synthesis of previous work done on the microscopic structure of cosmic
strings in realistic models is made and reveals that strings are expected to be
not only superconducting in the sense of Witten, but also generically
current-carrying, either at the GUT scale or at the electroweak scale. This
applies to any GUT string forming model leading to the standard electroweak
theory as a low energy limit. The current consists of charged vector bosons.
Cosmological consequences are briefly discussed.
