Sorry for the delay in replying: we’ve had company and it’s been full-on.
Earthdave, you’re arguing points I’ve already covered.
I don’t do “gotcha” questions, neither posing them (I hope) nor responding to them. The topic is far too important for that.
I’ll reiterate some of the other things I’ve already said to help.
- Gender dysphoria/incongruity is a real condition, or maybe conditions
- If someone says “I was born in the wrong gender”, there is no scientific understanding of what that means - where the seat of that feeling is - there is only an observation of that belief and statement
- It is important to treat people with GD/GI with kindness
- Many people in the UK were misdiagnosed: see what happened at the Tavistock Clinic
- The topic of gender has become weaponised by both left/liberal and right in the Anglophone world
- Given the terrible treatment of gay people when the DSM said they were suffering from a mental illness, the DSM and the psychiatric profession (like any other profession) can be seen to be potentially catastrophically unreliable. Certainly any assertion they make that has no scientific basis is suspect
I understand why you’ve ignored my question because, in fact, there is no scientific basis to treat gender dysphoria/incongruence as anything other than a mental disorder. I wondered if you believed there was any such basis, you saying you’re a biologist.
The correct categorisation of GD/GI is important because that forms the basis of the care sufferers receive.
If the medical profession amputated the limbs of people suffering from Body Identity Disorder (BID), it would quite rightly be viewed as grotesque–even though some argue for that.
There is no scientific understanding of what causes GD/GI and no long-term research was conducted before the medical profession embarked on its gender reassignment experiment.
The Amsterdam Cohort of Gender Dysphoria is an interesting, but rather more unreliable, study to quote. You will know the figures - 34 people receiving surgery in 1980, rising to almost 700 in 2015 - and that the study was published only three years later, in 2018. They did not allow a great deal of time for dissatisfaction to be found in the latter patients!
The evidence is increasingly clear that treating people with gender dysphoria/incongruity by surgical or endocrinological methods does not solve their mental health problems. The Finnish study is not without shortcomings - those you are those the study authors identified and explained 
- but is reliable enough to form a counterbalance to the career into unrestricted surgery.