Like ES cells, maGSCs can spontaneously differentiate into the three basic tissue layers of the embryo - and contribute to the development of multiple organs when injected into embryos.

BBC: NEWS | Health | Testicle cells may aid research

Meninges are the thin layers of tissue that protect the brain and the spinal cord under the skull.

CNN: Sheryl Crow: Brain tumor is a 'bump in the road'

At the moment colonies of human stem cells have to be grown on layers of tissue derived from mice.

ECONOMIST: Biotechnology in Singapore

Tissue cells, instead of performing the normal self-repair of damaged tissue, begin laying down excessive layers of collagen to help build a scar.

FORBES: Scar Wars

It also was conducted in a lab and so cannot account for the protection a human body might offer, such as layers of skin, bone and tissue.

CNN: Cell phones can affect sperm quality, researcher says