Originally a comment by Freemage on Mandatory affirmation.

Puberty blockers have been weighing on my mind, in particular, lately.

The whole claim is that the blockers prevent the development of sexual characteristics until the child has become old enough to be able to decide for themselves as an adult whether or not to transition. On first glance, this seems reasonable–I’m fine with adults transitioning, though I still agree to the GC in terms of what transition actually entails, and more importantly, permits. (Ie, an adult TIM still has no business in a women-only space, or participating in women’s sports, etc.) At that point, it becomes cosmetic surgery, which is generally up to the person getting it.

But this claim overlooks the fact that the whole reason adulthood exists as a legal category is cognitive development–you don’t suddenly become more able to make decisions about alcohol because you’ve taken 21 trips around the sun; you become more cognitively able to perceive the impacts of drinking after your body (most specifically, your brain) has developed to a point where you can make at least some amount of rational choice about such things.

But that development is both experiential and hormonal–if you stop the hormonal development with blockers, then you impede the very state of being that is supposed to enable you to decide better if you want life-altering surgery.

I know a family who adopted a child with fetal alcohol syndrome. She just hit her 18th birthday, but cognitively, she’s about 12 (and likely will still be at that stage for most purposes for the rest of her life). She’s a genuinely caring, friendly and happy kid–but the notion that she’s now at the point where she could be given the benefit of the doubt upon declaring that she wants to be considered a man is flat-out absurd. While hormone blockers probably aren’t as drastic in their inhibition of development as that, it seems pretty damned likely that the 18 year old who’s been on blockers since they were 12 is not going to be in the same position cognitively as one who actually has had all the brain development that comes with adolescence.