Examples of continually improving control over stem cells have been rolling in of late; here is one from the University of Texas: "We have developed a reliable molecular procedure which facilitates, via genetic selection, the differentiation of human embryonic stem cells into an essentially pure population of lung epithelial cells ... the procedure also can be used to create other types of highly-specialized cells. ... The method involves the use of protein markers under the control of cell-specific promoters to convert undifferentiated human embryonic stem cells into highly-specialized cells. The human embryonic stem cells were cultured on specially coated dishes and transfected with a lung epithelial gene regulator of a drug selection gene. ... It is a general technology for developing select cells from human embryonic stem cells. The technology has allowed us to develop a platform that could potentially be useful in the development of spinal cord cells, heart cells, nerve cells and others. ... transplantable alveolar epithelial type II cells can be explored as treatments for pulmonary genetic diseases, acquired lung disease, as well as lung trauma caused by car accidents, gunshot wounds and sports injuries. ... These are the cells that can potentially be used for regenerative lung repair."