First off nomenclature "Trans sexual" is pretty outdated terminology that no longer is used in the DSM for kind of good reasons.

Also generally speaking gender presentation is independent of actual gender. It's a common mistake made but what toys kids play with and how they like to dress has very little to do with identity and is only at best tangentially related. The idea that "Little Timmy likes Barbies get him to a gender clinic" is going to actually render anything other than a "some kids like Barbies" response is just anti trans hysteria.

Gender questioning is a known phase of development that may or may not stick particularly at a young age like seven. Heck gender questioning is something anyone can go through at any point in one's life and you may come out of it realizing that nope, you are actually cis. Inside the trans community we advocate for adults a good experimental phase by degrees and not to look at medical transition as the first potential solution until you feel solid in knowing yourself better.

For a kid a regular questioning period is around a few months to a year long. If they basically are consistent by the end of that year the evidence is that there's roughly a 95% chance that will be consistent over the next 5 years... With a little wobbling between binary and non-binary trans identities to be accounted forhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC9936352/#:~:text=Five%20years%20after%20an%20initial,back%20to%20binary%20trans%20identities. With trans people in general there's usually something seemingly unrelated that gets fixed by a successful social transition. Anxiety and depression can sometimes have physical symptoms. In trans accepting environments Social transition can target the root causes of stress so usually you can physically recognize the difference in someone suddenly flourishing...

Also 10 year olds do not make permanent body changes. If you are taking puberty blockers at age 10 the chances are better that you are doing so because you are experiencing precocious puberty. In Canada where I am treatment options for trans kids are limited to blockers so they can basically watch the kid. If you have a child who has a consistent identity over a span of years then they might recommend horomone treatments at age 16 to go through a puberty. This is done only with parental consent but requires a team including a social worker, psychiatrist/psychologist and endocrinologist and a pediatrician who basically have monitored the kid for several years. The first surgeries aren't available until legal adulthood at 18. There are no "children of 10 making unilateral decisions to change their bodies"- its a child of 16 and a panel of about 6 adults (assuming two legal guardians) doing a risk assessment and long term life planning that can be vetoed by any participant at any time.

Even when the door is open for medical help for trans kids it's still stacked against trans kids transitioning. Kids in the system have to stick to their guns against a lot of forces that look at them as a legal risk for suing the system for any permanent damages. It's less risky for institutions generally to just not intervene in natural puberty so they set a very high burden of proof to be absolutely sure beyond all reasonable shadow of a doubt that the kid is gunna be fine. If you hear anyone talking about it being as easy as just scheduling an appointment quite frankly they are full of shit.