The goal of this project is to provide conclusive observational evidence that jets from young stars rotate. This evidence will finally validate widely supported models that explain how bipolar jets can extract angular momentum during gravitationally collapse, thus allowing the disk to accrete onto the infant star. Our team recently published a series of results, based on high angular resolution data from the Hubble Space Telescope, which revealed the very first observational indications of jet rotation close to the jet base. However, the interpretation of our results has become a matter of rigorous debate. This is a crucial moment to follow up on these exciting detections. We must establish that gradients in Doppler shift perpendicular to the direction of jet propagation are justifiably interpreted as a rotation of the flow. This can be done by performing a number of crucial observational checks. Our objectives are therefore to establish that Doppler gradients are commonly observed in many jet targets, that they are also observed at every evolutionary stage of stellar birth, and that there is agreement between the sense of disk and jet rotation in each system. In meeting these three objectives, we expect to achieve our goal of providing long-awaited observational evidence that jets from young stars rotate. Our findings will then form the only existing observational basis for validation of the magneto-centrifugal mechanism of jet launching. Furthermore, the results will finally provide a means of discriminating between steady-state MHD models for jet generation. Providing incontrovertible evidence that jets extract angular momentum from protostellar systems has far-reaching implications, as these models are also standard for launching jets in very diverse objects from brown dwarfs to massive black holes in quasars, all of which still require observational verification.