Having successfully used "blank slate" stem cells to help bald mice grow hair, researchers say the implant technique could lead to a cure for human baldness.

In a study posted on the Web site of the journal Nature Technology in advance of its April publication date, scientists confirm a long-held suspicion: that hair follicles contain the "blank slate" stem cells.

Researchers from the University of Pennsylvania identified stem cells in the hair follicles of mice. When transplanted into skin, they grew into hair follicles.

"We've shown for the first time these cells have the ability to generate hair when taken from one animal and put into another," co-author Dr. George Cotsarelis told The Associated Press in a telephone interview.

According to the University of Pennsylvania dermatologist, the project marks the first time such stem cells have been used to successfully induce hair growth.

"You can envision a process of isolating existing stem cells and re-implanting them in the areas where guys are bald."

So-called "blank slate" stem cells are distinct from the embryonic stem cells around which an intense political debate has developed.

Created in the first days after conception, embryonic stem cells are the basis for the more than 200 different types of cells in the developed human body.

Harvesting such cells requires the destruction of an embryo.

Scientists have long-suspected that hair follicles contained the adaptable stem cells. However, they have been largely unable to isolate the cells in humans.

With further study, scientists have new hope they can move closer to tracking the genes.

Although the success with the bald mice is being hailed as a breakthrough in the field of hair research, some caution that a cure remains out of reach.

"Like with any stem cells, the amount of information needed to get us from a stem to a fully developed organ is a lot," Stanford University biologist Anthony Oro told the AP.

"It will require a lot of things to go right and we are still along way off."

Two drugs now marketed as hair growth aids, known commercially as Rogaine and Propecia, post about $100 million US in annual sales.

The American industry built around the fight against baldness has grown to an estimated $1 billion. Most of that is spent on surgical hair transplant procedures.