  Measurements of open charm hadro-production from CERN and Fermilab
experiments are reviewed, with particular emphasis on the absolute cross
sections and on their A and sqrt(s) dependences. Differential pt and xf cross
sections calculated with the Pythia event generator are found to be in
reasonable agreement with recent data. The calculations are scaled to
nucleus-nucleus collisions and the expected lepton pair yield is deduced. The
charm contribution to the low mass dilepton continuum observed by the CERES
experiment is found to be negligible. In particular, it is shown that the
observed low mass dilepton excess in S-Au collisions cannot be explained by
charm enhancement.
