Background: Adult human mesenchymal stem cells retrieved, from the post-partum human umbilical cord Wharton jelly (hUCMS), have recently gained growing interest due to their morphological and functional properties. Objective: The main purpose of our work was to examine morphology and functional properties of hUCMS retrieved from healthy women as compared to those with obesity, or gestational or type 2 diabetes mellitus, under fair metabolic control. Possible differences between groups could shed light into the potential use of these cells for the cell therapy of a variety of diseases, regardless of the obesity/ diabetes status of the donor mothers. Additionally, information on how the maternal disease may affect the cord-derived stem cells, hence possibly newborn children would be important. Methods: We have studied obese/diabetic or normal donor post-partum umbilical cord-derived hUCMS, either in basal or during differentiation protocols into several cell phenotypes and the definitive endoderm. Immunomodulatory properties of these cells, in terms of inhibition of activated lymphocyte proliferation, also was examined. Results: According to our preliminary results, there are functional differences, as assessed by cell and molecular assays, in terms of both, differentiation and immunomodulatory potential, between the cells derived from normal as compared to obese/diabetic mothers. Conclusion: The findings seemingly indicate that the uterine environment of obese/diabetic mothers is quite distant from normal, regardless of metabolic control. Hence hUCMS extracted from obese/diabetic mothers do not appear to be suitable for cell therapy clinical protocols but more studies are required.