  In multi-Higgs-doublet models the alignment in flavour space of the relevant
Yukawa matrices guarantees the absence of tree-level flavour-changing couplings
of the neutral scalar fields. We analyze the consequences of this condition
within the two-Higgs-doublet model and show that it leads to a generic Yukawa
structure which contains as particular cases all known specific implementations
of the model based on Z_2 symmetries. All possible freedom in the Yukawa sector
gets parametrized in terms of three complex couplings. In spite of having
flavour conservation in the neutral scalar couplings, the phases of these three
parameters represent potential new sources of CP violation.
