“For a long time, we’ve been saying this is 10 years away,” says Robert Bernstein, a dermatologist in Manhattan who specializes in hair transplantation. “But now it actually might be less.”

Of all the parts of the body to create in a lab, hair could seem like the simplest. It’s a strand of protein filaments wrapped around one another. Hair doesn’t have to “function” in the way of a liver or brain; it just has to sit around and grow and not fall out.

But hair is much more complex to make than many researchers initially expected. To produce a single, hardy strand, the body relies on thousands of stem cells called dermal papillae at the base of each hair follicle. Human scalps contain about 100,000 hair follicles, but their life spans are limited: As dermal papillae disappear over time, follicles “miniaturize” and become dormant. (In this way, a bald person’s head still has hair, technically, but only in wiry strands that are the result of dormant follicles with only a few hundred dermal papillae.)

When a hair follicle goes dormant, it cannot be restored. So any ads for hair “restoration” that you might see are actually ads for surgical transplantation of hair follicles—taking hair from one part of the scalp and moving it to another. The procedure can cost about $10,000, and its results are limited by how many vital hair follicles a person has available to move.

Doctors in some parts of the world will move a person’s body hair (back or underarm) onto his or her head, but most surgeons agree the aesthetic outcome is not pleasing. Conceivably, a person could have someone else’s hair put onto their own head, but that would require a blind eye to the ethics that prohibit the purchase of human organs.

The answer, then, lies in generating new hair. This science is progressing alongside the creation of other bodily structures in what is known as cell therapy, a promising area of medicine in which therapies are derived from a person’s own stem cells. Pancreatic cells could replace those that stopped producing insulin in people with type 1 diabetes. Immune cells could be used to attack tumors. Nerve cells could be used to repair spinal-cord injuries. And, of course, hair follicles could be used to cover hairless skin. Using cells from a person’s own body minimizes the risk that the immune system will reject the hair transplants (as happened to Arrested Development’s Dr. Tobias Fünke).

The ultimate goal among scientists is to create “hair farms,” as the entrepreneur Geoff Hamilton and others put it. Hamilton is the CEO of Stemson Therapeutics, a San Diego–based start-up that is working on cloning hair follicles. It involves growing hair from stem cells—not fetal, but stem cells derived from a person’s own skin or blood—and implanting hair follicles rich with dermal papillae into the space around a person’s old, shrunken, dormant follicles.