  The influence of the nucleon-nucleon final state interaction (FSI) on
properties of the meson production amplitude near threshold is discussed. For
the nucleon-nucleon interaction a simple Yamaguchi potential as well as
realistic potential models are considered. It is shown that FSI effects cannot
be factorized from the production amplitude. The absolute magnitude of FSI
effects depends on the momentum transfer (or on the mass of the produced meson)
and hence is not universal. Only in the case of the production of rather heavy
mesons like eta' or phi FSI effects become universal. The Jost function
approach to FSI effects is critically examined.
