The measurements of the forward-backward asymmetry in Z -> c cbar and Z -> b
bbar decays are among the most precise determinations of sin^2(theta)_W. In
this paper the results obtained by the DELPHI experiment at LEP with three
different analyses are reviewed together with the impact of the combined LEP
result on the global Electroweak fit.Comment: 7 pages, RevTeX, fonts changed in 2 eps file