Stem cells can be used in medicine to treat a range of diseases. Explain the benefits and risks of using stem cells as a medical treatment.

Stem cells can be used to treat a large variety of different diseases and to repair damaged tissues, for example in Parkinson’s disease, diabetes and spinal cord injury.

Because stem cells are derived from the patient’s own body or are of a universal type, they are not rejected by the immune system and do not require matching, unlike donor organs.

However, when stem cells are expanded in the laboratory there is a risk of contamination or mutation; such altered cells could be transferred to the patient and cause tumour formation or other complications.

Stem cell therapy is still relatively new, so the long‑term safety and efficacy are unknown and there is no guarantee that the treatment will work.

Finally, the use of embryonic stem cells raises ethical concerns, as the cells are harvested from embryos that are destroyed in the process.