This test while not performed frequently, provides a good model of sperm penetration of the egg.  The hamster eggs have to be treated first with enzyme to remove their zona (clear membrane) so that human sperm are able to penetrate them.  Without enzymatic treatment to remove the zona you will not get cross species penetration of the eggs.

The denuded hamster eggs are exposed to human sperm, and after the incubation period the eggs are scored for sperm penetration.  The The test represents a fairly reliable index of the sperm’s ability to attach to the egg membrane, and to penetrate the egg.  Attachment of sperm to the eggs surface, and penetration of the egg membrane is the first step in the fertilization process.  If human sperm are unable to penetrate the egg then it is still possible to have fertilization using the ART (advanced reproductive technology) technique of ICSI (intracytoplastmic sperm injection).  This procedure is used to insert a single sperm into each egg.  ICSI is carried out in a reproductive laboratory on eggs that have been obtained by IVF (in vitro fertilization) technology.