Babies born with congenital defects often require surgery. Surgeons face a problem, however — in adults, tissue for repair is borrowed from other areas of the body, but babies don’t have enough tissue to spare. Sometimes surgeons use teflon — certainly not an ideal replacement. The laboratory of Dario Fauza, Harvard Medical School instructor in surgery at Children’s Hospital and the Harvard Center for Minimally Invasive Surgery, has been pursuing the goal of having a ready supply of fetal tissue on hand at birth to correct congenital abnormalities. The work is sponsored by U.S. Surgical Corp. In the past few years, Fauza’s lab has worked to solve the tissue replacement problem by collecting a small amount of the fetus’s tissue in utero and using the cells to engineer replacement tissue. The tissue has time to grow in culture while the baby comes to term and is ready for implanting at birth. In their latest study, Fauza’s team has potentially sidestepped the need even for harvesting fetal tissue by finding a source of usable fetal cells in an unlikely and much more accessible place — amniotic fluid.