Mental health counseling would be a start. There is nothing biological or genetic going on with this. Scientists reject that notion. Most of these people need mental health help to align their gender with their sex and aren't getting it. It's sad that people are so afraid of making them feel bad about themselves that they won't get the help they need.
I certainly do favor the private, locking "family" bathrooms at most public locations. That's a benefit to many people, parents with small children of the opposite sex as well as anyone who is transgender.
The epigenome: the next substrate for engineering | Genome Biology | Full Text
From this article these few paragraphs summarize the complexity of the mechanics of the epigenome (chromatin) activity on the DNA that goes into play during transcription which is the process of converting the DNA composed of nucleotides to the construction of molecules that function in the body (proteins composed of amino acids).
"There exist a surprisingly large number of epigenome modifications. The combinatorial interactions between these modifications and other chromatin-bound proteins increase this complexity even further. In fact, most chromatin states that are associated with regions such as active promoters and enhancers are characterized by specific combinations of chromatin modifications [
72]. Why did this combinatorial complexity evolve? One reason could be that single modifications alone are not sufficient to account for all the distinct states that need to be specified or marked. Perhaps a more intriguing possibility is that combinatorial interactions set the stage for context-dependent regulation and enhance locus-specific recruitment.
With context dependency, one modification could mask, modulate, or enhance the binding interaction of a reader of a second modification."
"Combinatorial modifications could also prime a gene to follow one of multiple possible paths. Certain domains of the embryonic stem (ES) cell genome possess both activating and repressive histone modifications, known as bivalent domains; these are typically enriched at developmentally important genes [
76,
77]. It is proposed that genes that have bivalent domains are poised for either activation or repression, depending on the differentiation path that the cell ultimately follows.
Gene expression is precisely controlled in time and space by the integration of this diverse array of PTM signals and the actions of multiple chromatin-regulating factors operating in multifactorial ways [3, 78]."
This last paragraph is the salient paragraph IMO regarding the transgender issue or any medical issue.