Hey, Claire, thanks for posting this. Yarhouse is one of the best Christian authors on gender dysphoria. I used to have a copy of his book Understanding Gender Dysphoria. He proposes three ways of interpreting gender dysphoria through scripture:
1. Natural diversity, which is to be embraced and celebrated
2. An unfortunate result of fallen human nature, a developmental abnormality not any different from autism or a cleft palette
3. Outright sin, damnable delusions
Yarhouse is of the second viewpoint, and I would say I am as well.
He is one of the only Christian authors who acknowledge the organic causes for gender dysphoria. However, his approach to treatment is not the best. His approach is basically "do only the very minimum to achieve a level relief that allows you to live safely". Most of us really do need to transition, and his approach only serves to drag that out over as long of a time as possible, extending the pain and suffering.
But, in a world of Christians who outright hate and condemn transgender people, he is one of the most reasonable voices out there.
Another good resource is Mark Wingfield, a Southern Baptist pastor from Texas who put his career and reputation on the line by publicly writing about the nature of gender dysphoria and why being transgender is not a sin. I have had email correspondence with him and he is a very helpful and kind person.