New 3-D printing devices are affordable and increasingly common in hospitals and labs. Prototyping new devices can now happen as simply as making a digital design and printing it out. This era of universal manufacturing is raising a new set of questions for the U.S. Food and Drug Administration, which is charged with regulating medical devices.

The agency has already okayed many 3-D printed devices, including joint implants and surgical cutting guides, which must go through a prescribed process for testing and approval. “The FDA doesn’t care what tools are used to make things,” says Andy Christensen, who oversees medical devices for 3-D printing pioneer 3D Systems. “They care about the end products.”

The approvals process may change if medical clinics begin using 3-D printers to produce personalized versions. In a written statement, the FDA said that medical devices constructed using 3-D printing technology are subject to the same regulatory review standards as devices constructed using traditional manufacturing practices. However, the agency added, “[a]s 3-D printing technology develops, the FDA may provide further clarity on quality control issues such as material qualifications and sterility.”

Looking deeper into the future, though, it’s anyone’s guess how the FDA might monitor the safety and quality of bioprinted organs, should they become a reality. Asked how the FDA would handle such “products,” an FDA spokesperson wrote that the agency “will continue to monitor technology trends, and provide a path from research to market.”