How close are scientists to growing fully functional human organs in a lab?

The answer

Lab-grown organs have progressed remarkably. Simple structures like bladders and tracheas have been implanted in patients since the 2000s by Anthony Atala's team at Wake Forest. By 2024, researchers can grow complex organoids - miniature versions of kidneys, livers, and brains - for drug testing. In 2023, scientists at the Weizmann Institute grew synthetic human embryo models to day 14 without sperm or eggs. 3D bioprinting using patient-derived cells can now create vascularized tissue constructs. United Therapeutics is developing bioengineered lungs using decellularized pig scaffolds reseeded with human cells. The primary remaining challenge is vascularization - growing the intricate blood vessel networks needed to sustain organs larger than a few millimeters thick.