This is from the BBC article.
Cross-sex hormone therapy is used to help people transition to a different gender from the one they were born into.
The same sentence appears in the linked article (by a different author) about the mother trying to stop her daughter being given testosterone.
But what does it mean? Nobody ever explains what they mean by "transition to a different gender". They can't be using gender to mean sex, because people can't change sex. If it's not being used as a synonym for sex, is it correct to say that people are "born into" a gender? If they are, surely it's only in the sense that a gender is imposed on them because of their sex, so since that comes from society, not the individual, then that can't be changed by superficially changing someone's physical characteristics, because it's not about the individual, it's about society.
This seems to be one of those statements which people repeat as though it makes sense, when it's obviously meaningless as soon as you start to analyse what it might mean. And this absurd idea about changing someone's gender, without being clear what is actually being changed, is what leads to children being given harmful medication.