In the study of embryonic stem cells, stem cells representative of naïve and primed pluripotency have been well established in the forms of embryonic stem cells (ESCs) and epiblast-derived stem cells (EpiSCs). In this study Kinoshita et al. fill the gap between early and late pluripotency in describing an intermediate state; formative stem (FS) cells. FS cells differ from both ESCs and EpiSCs, a difference beautifully exemplified by their relative contribution to chimeras. Compared with ESCs, which readily contribute to chimeras, FS chimera contribution is less frequent, and their contribution is less evenly distributed. EpiSCs on the other hand do not generally contribute to chimeras at all. FS cells were established by culturing E5.5 epiblasts, or ES cells, in N2B27 media supplemented with a low dose of Qkine Activin A alongside a Wnt inhibitor and pan-retinoic acid receptor inverse agonist. We are proud our growth factors could be part of such an exciting finding!