Keira Bell is not the only case, though. If you listen to the Stephen Nolan podcasts you will hear examples of others. Episode 5 is the one about children transitioning.
Of course it is true that not all children confide in their parents about everything - in fact I'd be surprised if many do, and it's not necessarily always a bad thing. Children need to learn how to think for themselves and make mistakes before they leave home, or they'd be doing it for the first time when they are on their own.
That is not the point, though. Just because something happens doesn't make all instances of its happening right, or mean that it should be encouraged to continue. Also, we are not talking about 16 year olds taking the pill, or drinking cider in the park. These are pubescent children.
It's bad enough that schools are teaching that there are over 100 genders, although if the DofE follows the BBC that may soon stop, but if 10 year olds who are already confused by this are getting pandered to by cosmetics companies their confusion is likely to get worse, and as long as consultants are persuaded/coerced into thinking that any child who presents with body image issues is potentially transexual the number of regrettable and terrible cases will proliferate. Again, the position of the medical profession is discussed in episode 5 of the podcasts. I really recommend that you listen to them with an open mind. They are not pushing one 'side' or another, and participants are given time to put their case in their own way without the interruption that usually happens on TV and radio interviews.