Stem cells originally came from two main sources, embryonic stem cells and adult tissue which contain adult stem cells.

Scientists have more recently been able to take adult cells and genetically re-programme them into so called ‘induced pluripotent stem cells’ (iPSC’s) which could behave like embryonic stem cells. This eliminates the need to derive cellular material from developing embryo’s.

• Embryonic stem cells are obtained from embryos at an early stage of development. Sources include those extra embryos that were created but not used during in vitro fertilisation treatment and from embryos aborted during a termination of pregnancy.
• Adult or somatic stem cells exist in many tissues of the body. They are present for tissue repair. They are activated by tissue injury in order to initiate the recovery process. They can be manipulated in the laboratory into cells with defined physiological functions. In so doing a potential for cell based therapies is fulfilled.