My post is quite measured really - basically saying either the child is trans or they aren't and it's too early to tell and carry on as you are. Not particularly radical.
Admittedly, 'innate' was probably the wrong word - I think what I meant was gender (identity) is something that is within us and forms part of our identity in a different way to pretending to 'be an animal'. It informs how we view the world, interact within it and how others treat us. I was trying to make the point that the comparison in wanting to be an animal isn't really appropriate, rather than arguing that gender identity is 'innate' because that's not really right.
Blockers are generally safe - www.eurekalert.org/news-releases/842073
And there's also the argument that even if blockers did pose a risk to bones, the risk of not giving them on a trans teen's mental health is far higher than the risk of blockers. Going through puberty of the opposite sex can be traumatising. Trans youth are at far higher risk of depression, anxiety, self-harm and suicide than the general population pubmed.ncbi.nlm.nih.gov/32345113/
Again though, this is a really individual thing and blockers should be prescribed in conjunction with mental health support and counselling not as a solution for everyone who asks. The point is, they should be available because some people need them.
I'm not saying that all children who tell you they're the opposite sex/are transgender really are - just that some of them will be. Denying this won't change who someone is - if it did then there wouldn't be that many trans people in the world.
This is quite interesting - www.gendergp.com/detransition-facts/
Most people who end up on blockers go on to fully transition. But this conversation started with OP and a 5yo. They are way way off thinking about blockers, medication or anything else. If their DC becomes distressed and wants to fully socially transition, that would be the first step - but it doesn't sound like they're there yet. And may not at all.
Have you actually met any trans people and listened to them talk about their experiences?