Does matter wave amplification work for fermions?

We discuss the relationship between bosonic stimulation, density fluctuatio ns, and matter wave gratings. It is shown that enhanced stimulated scatteri ng, matter wave amplification, and atomic four-wave mixing do not require m acroscopic occupation of a single quantum state. These processes are in pri nciple possible for fermionic or nondegenerate samples, if they are prepare d in a cooperative state. In practice, there are limitations due to short c oherence times.