Infertility remains a great challenge to reproductive biology in today’s world. One of the critical steps in the reproductive process is the embryo implantation; an inability of the blastocyst to attach to the epithelial wall of the human endometrium is a leading cause of both natural and in vitro infertilization. In in vitro fertilization, this is the principle cause of the 70% failure rate of successful embryo transfers. This attachment of the blastocyst to the endometrium is initially mediated in part by an L-selectin adhesion system. This system consists of L-selectin on the trophoblasts, or exterior cells of the blastocyst, attaching to oligosaccharide ligands on the surface of the endometrium. This adhesion system is weak however, and is followed by a secondary integrin-ligand interaction. In the lab we are working to understand the mechanisms of both the primary and secondary attachment system. Currently, we are quantifying the bond strength of L-selectin to its ligands by applying shear forces due to fluid motion through a custom-build Parallel Plate Flow Chamber and determining the detachment strength of these bonds.