Clinical studies in which tissue is grown from a patient's own cells and then implanted to address a medical issue are no longer remarkable; many are currently taking place, with new studies starting all the time. A surprising number of these are focused on pediatric medicine, but the technologies have the prospect of much broader application. Here is an example: "Xeltis, a biomedical technology company developing growing, living and self-healing cardiovascular implants using tissue-engineering technology, has announced conditional approval by the Paul Erlich Institute (PEI) in Germany to commence the first clinical study of its tissue-engineered cardiovascular grafts. The prospective, single-center study will evaluate the safety and efficacy of Xeltis' autologous tissue-engineered vascular grafts in pediatric patients ... Due to their expected longevity, ability to grow and very low risk of thrombosis and infection, these new grafts hold the promise to deliver life-saving therapy for children born with cardiovascular defects. ... Today's grafts are made of artificial material or of animal tissue, both having significant limitations such as potential rejection, limited durability and calcification over time. In contrast, Xeltis implants are 'regrown' from the patients' own cells. The resulting implants are, therefore, designed to behave like native organs, with unlimited durability, no risk of rejection and no need for anticoagulants. In addition, children implanted with today's grafts face the critical problem of outgrowing their implants, requiring them to undergo one or more reoperations, each with an increasing rate of morbidity. Because Xeltis' implants have the ability to grow as the child grows, they may remove the need for reoperations."