Currently it is the hope of both patients and investigators that human progenitor cells and stem cells can be widely used to replace dysfunctional cells within a tissue. It is speculated that such cells may prove to have the potential to treat or cure a myriad of diseases, including Parkinson's and Alzheimer's diseases, heart disease, diabetes, stroke, spinal cord injuries, and burns. A major goal in this area of research is to identify potential new sources for the isolation of progenitor cells or stem cells, without raising the ethical issues involved in embryonic stem cell research. Despite the widespread and well-established use of amniotic fluid cells in routine prenatal genetic testing, current knowledge about the origin and properties of these cells is limited. A wide variety of different origins has been suggested for the mixture of cells within amniotic fluid. Recent observations on cell cultures from amniotic fluid and on amniotic epithelial cells provide evidence that they may represent new sources for the isolation of cells with the potency to differentiate into different cell types. Are these cells suitable for use as primary cell systems for basic research? Do these cells provide a new source for research on stem cell biology? Can amniotic fluid cells be used to develop new approaches in tissue engineering? In this article the authors review the current state of knowledge about these cells, focusing on these questions.

Keywords: Amniocentesis, Amniotic Fluid - cytology, Ethics, Medical, Reverse Transcriptase Polymerase Chain Reaction, Stem Cells - cytology, Stem Cells - metabolism, Tissue Engineering