The invention relates to the in vitro transfer of the Sperm Adhesion
Molecule 1 (SPAM 1) to spermatozoa. The SPAM1 protein can be obtained
from the epididmys or the uterus and should have an intact lipid anchor.
The SPAM 1 protein attaches to the surface of mammalian spermatozoa via
it's lipid anchor in an in vitro environment in order to increase the
sperm's capability of fertilizing an egg.