What Controls the Expression of the Balding Gene?

Hi Doctors,
As an avid reader of this blog I have developed a pretty broad understanding of the genetic balding process and the various treatment options available, and for that I thank you. The one question that has recently surfaced involves gene expression. I know your not a geneticist, however,with your knowledge in both biology and and androgenetic alopecia I’d assume this would be within your general fund of knowledge. An individual can carry the gene for genetic hairloss, but not express it.

My question is what is controlling the expression? I’m assuming environmental variables are involved (stress, maybe nutrition to a certain extent) but is there a biological explanation? From my brief studies in biology, I remember hearing something about the role of transcription factors in the expression of particular genes. Your thoughts are much appreciated.

You said about what I know of the mechanisms for gene expression. It’s beyond my scope. You can use Google to find articles and theories about gene regulation, but I’m posting this in case a geneticist (or armchair geneticist) would like to contribute in the comments.