The document discusses different types of stem cells including adult stem cells, fetal stem cells, and embryonic stem cells. It notes that adult stem cell research has had 74 clinical successes in treating various diseases and conditions, while embryonic stem cell research has had no successes and risks tumor formation. The document raises ethical issues with extracting stem cells from embryos and fetuses as it requires their destruction. It concludes that adult stem cells are a promising research area that avoids ethical issues.