Here is a film that tugs at the heartstrings as it painstakingly covers the lives of 10 patients participating in stem cell research trials in the US. From a quadriplegic high-school basketball star to a mother with recurring cancers, the subjects experience remarkable recoveries thanks to this medical revolution. One of the most moving moments is when Ryan, the teenage athlete, returns home four months after his initial treatment and raises his hand to greet his loved ones at the airport, a progress that would have been unimaginable without the advent of stem cell therapy.

While the treatment has proved extraordinarily successful in combating incurable diseases, the research remains controversial as it involves the use of human embryos, which is inevitably intertwined with the abortion debate hotly contested in US politics. Furthermore, pharmaceutical corporations are hostile to a medical technology that would significantly reduce the traditional reliance on medications. Indeed, in the case of cancer patients, as stem cells can multiply into healthy cells to repair damaged areas from within, the research aims to reach a point where chemotherapy would no longer be needed. Once banned by George W Bush, federal funding for stem cell studies has gradually increased, though it remains mostly awarded for non-embryonic research.

This documentary is an effective emotional appeal, though perhaps it could have begun to examine the scientific side of the research earlier than the halfway point of a two-hour film. Nevertheless, the closing image of a woman with corneal damage now able to enjoy indoor mountain climbing swells with the optimism that the research will be allowed to continue on its journey.

• Ending Disease is released on 5 November on digital platforms.