Researchers already found some genes, that influence the hair cycle and hair growth. In 1998 Dr. Christiano
(Columbia University) found the hairless-gene, that is responsible for a rare form of hairloss (http://www.columbia.edu/cu/record/23/14/13.html).
Some time later she published the finding of the nude-gene, another gene, that influences the hair cycle (http://cumc.columbia.edu/news/journal/journal-o/fall-1999/gene.html).
In 1999 Dr. Crystal (Cornell University) showed, that the sonic-gene can reactivate inavtive hair follicles in mice (http://www.findarticles.com/cf_dls/m1200/18_156/57799550/p1/article.jhtml). This is important, as inactive human hair follicles can be reactivated about 10-15 years after they stopped producing hair. So it will be possible to restore the hair, that you had 10-15 years ago with this method. Nevertheless the sonic-gene may increase the activity of oncogenes (genes, that cause cancer), so it probably wonīt be used in humans. Other genes have to be found, that also reactivate inactive hair follicles, but donīt have side-effects (so-called trigger genes). It will even be possible to create completely new hair follicles by using gene therapy. In 1998 Prof. Elaine Fuchs (Howard Hughes Medical Institute http://www.hhmi.org) published, that the molecule ß-catenin can create new hair follicles in mice. This process is quite complicated, so more research is needed, before human studies can be done. But then even totally bald people can get full hair again. More information about the research of Prof. Fuchs can be found e.g.
As it was already said, gene therapy will be able to cure all sorts of hairloss, like alopecia universalis, alopecia areata and of course hereditary hairloss (androgenetic alopecia) in men and women, as the principle is always the same or similar: The therapeutic gene is delivered highly selevtively to the hair follicles by a gene vector. There are no problems in principle with gene therapy. The existing delivery methods must be improved and the perfect trigger gene (a gene, that reactivates hair follicles) must be found.