Currently, there is enormous interest in stem cells as a new treatment modality for regenerative medicine, commencing when human embryonic stem (hES) cells were first cultured from spare in vitro fertilisation‐derived embryos. Emerging evidence also suggests that somatic stem cells may have greater differentiation potential. Stem cell research is now in an exciting phase of development and has the potential to dramatically influence therapeutics as hES cell derivatives and/or adult stem cells are applied to regenerative medicine or to deliver gene therapy. Human ES cells show apparently limitless proliferative potential and differentiation capacity into all tissue types. Adult stem cells are rare cells, which maintain the tissue in which they reside. The challenges facing the use of hES cells and adult stem cells in medicine are highlighted and examples of their use in laboratory studies and the clinic are given. Adult stem cells have been identified in diverse tissues, including human bone marrow, breast, prostate, brain and liver. We hypothesised that adult stem cells reside in the endometrium, a highly proliferative, cyclically regenerating tissue. Our research has demonstrated, for the first time, that human endometrium contains a small population of epithelial cells (0.22%) and stromal cells (1.25%) that exhibit stem/progenitor cell behaviour in vitro; clonogenicity. The progeny in these colonies have been characterised and growth factors supporting clonogenicity identified. The goal is to examine the role of putative endometrial stem/progenitor cells in proliferative disorders of human endometrium, such as endometriosis, adenomyosis, endometrial hyperplasia and endometrial cancer, and the action of hormone‐replacement therapy on the post‐menopausal endometrium.