The current roadblocks to hematopoietic stem cell (HSC) therapies include the rarity of matched donors for bone marrow transplant, engraftment failures, common shortages of donated blood, and the inability to expand HSCs ex vivo in large numbers. These major obstacles would cease to exist if an extensive, bankable, inexhaustible, and patient-matched supply of blood were available. The recent validation of the embryonic hemogenic endothelium (blood vessel cells lining the vessel wall give rise to blood stem cells) has introduced new possibilities in hematopoietic stem cell therapy. We have set out to learn the programs in the embryo that allow for endothelial to HSC transition, and have found a minimal number of factors required to generate blood cells from blood vessels, turning back the clock in mature blood vessels. The work, through CIRM funding, has resulted in multiple scientific publications and a patent, all contributing to a body of work that contributes to a deeper understanding how blood stem cells may be generated in vitro for translational applications.