It's not just about lack of hair but rather a problem with new hair that is made.
A defect with stem cell activation seems to produce hair that is so small it appears invisible to the naked eye. This is what produces the classic bald spot or receding hairline.
A report in the Journal of Clinical Investigation says it may be possible to cure male baldness by restoring the normal function of these stem cells.
Researchers hope to develop a cream that could do just that.