  The observed pattern of lepton mixing does not give an evidence of the
seesaw. It is easier to disprove seesaw showing that one of the alternatives
gives dominant contribution to the neutrino mass. We consider alternative
mechanisms based on (i) small (tree level) effective couplings, (ii) small VEV,
(iii) radiative generation of masses, (iv) protection by SUSY breaking scale or
by $\mu$-term, (v) small overlap of wave functions of the left and right handed
neutrino components in extra dimensions. Seesaw can be the mechanism of
suppression of the Dirac mass terms and not dominant mechanism of the neutrino
mass giving just a sub-leading contribution.
