  We investigate the phase diagram of QCD at small chemical potentials, ie,
when chiral and flavour symmetry breaking involves the pairing of a quark and
an antiquark. The phase diagram of two-flavour QCD at small chemical potentials
involves chiral symmetry restoration and charged pion condensation. We extend
previous studies of the topology of the phase diagram, in sections with high
degree of symmetry, to the physical case of fully broken flavour symmetry,
using generic thermodynamic arguments. We argue that the extension is unique
and present the result. In three flavour QCD the phase diagram for chiral
symmetry restoration is less well constrained. However, we argue that present
lattice data allows just two different phase diagrams, which we discuss.
