How are stem cells grown in the laboratory?

Stem cells are grown in the laboratory through a process called cell culture, which is based on the ability of stem cells to proliferate in a culture medium. 

To grow stem cells in a laboratory, stem cells are placed in a culture dish that contains a culture medium. This is essentially a nutrient broth that is optimized to support the growth of different types of stem cells. The stem cells that are introduced into the culture medium attach, divide, and spread across the surface of the dish. 

As cell division progresses, the culture dish becomes increasingly more crowded and eventually needs to be re-plated in a process known as subculturing. The subculturing or re-plating process is repeated periodically over several months resulting in millions of stem cells derived from the original cells. 

Batches of stem cells can be frozen at any point in the process and transported to other laboratories, allowing for further culture and experimentation in different research settings.