  Within the framework of the two-Higgs Doublet Model (2HDM), we attempt to
find some discrete, non-abelian flavour symmetry which could provide an
explanation for the masses and mixing matrix elements of leptons. Unlike the
Standard Model, currently there is no need for the flavour symmetry to be
broken. With the GAP program we investigate all finite subgroups of the U3
group up to the order of 1025. Up to such an order there is no group for which
it is possible to select free model parameters in order to match the masses of
charged leptons, masses of neutrinos, and the Pontecorvo-Maki-Nakagawa-Sakata
mixing matrix elements in a satisfactory manner.
