The idea of an “artificial womb” has been explored in literature, science fiction, and film for almost a century. Full ‘ectogenesis’—growing a human from an embryo entirely within an artificial environment—might have profound implications for society, but is far from reality. However, recently published work with an animal model has described a technique for supporting extremely premature newborn lambs (equivalent to 23 weeks of human gestation) in a liquid environment with an artificial placenta for a period of up to 4 weeks. The apparent success of this model has led to suggestions that it could be trialled in humans in the near future. If it were successful, artificial gestation might represent a paradigm shift in neonatal care. It could radically improve the prospects for infants born around the current borderline of viability. It may also shift the current threshold of viability and make it possible to save infants who could not be saved with current technology. However, artificial gestation will raise considerable ethical challenges—both during the first stages of its evaluation in humans, and, if successful in its application to neonatal care.