  The problem of quark-lepton families is discussed in the "bottom-up"
phenomenological approach to the extensions of the Standard model. It provides
the possibility of the {\it Horizontal unification} of the three known families
on the basis of horizontal gauge flavor $SU(3)_H$ symmetry. The new generations
of quarks and leptons can exist. If unstable and mixed with light fermions,
they should contribute the CKM matrix. If stable and decoupled from known
families, new generations can provide new candidates for dark matter.
