I can see where your mind would go there. That’s a good question.Why don’t you apply this universally?
If someone is born with a BRCA mutation and opts for a preemptive mastectomy due to breast cancer risk, is that an act of willful defiance?
If someone born with a cleft lip and palate has reconstructive surgery, is that an act of willful defiance?
If someone is born deaf, is it an act of willful defiance to get a cochlear implant?
In your opinion, based on your precedent, what medical care should be allowed for any congenital or genetic condition? None? God “made them that way”, so deal with it?
A double mastectomy to preempt a cancer diagnosis carries an entirely set of motivations than a double mastectomy as part of a gender transition. God is after our heart, and it is our motivations that matter to Him. Christianity is about a humble submission to God’s will and teachings. Transgenderism is a willful statement of personal autonomy. It says to God that “I am in charge, not you!”
I’m not saying people shouldn’t be trans because of my personal religious beliefs. People can have whatever religion they want. I wouldn’t have even brought it up except to answer the question.