Almost 1,400 children applied to have gender reassignment surgery in the UK last year, with referrals for young transgender people doubling.

The statistics from The Tavistock Clinic in London suggest that society is becoming more accepting of gender dysphoria as young people experiencing difficulties in the development of their gender identity are starting to get the help they need.

But it's still a tricky issue for many parents who are trying to understand whether their child is going through 'a phase' or is struggling with gender identity issues. It's something that even Angelina Jolie may understand.

In 2014, her then eight-year-old daughter said she no longer wanted to be known as Shiloh – she’d rather be called John. Her dad, Brad Pitt, disclosed in an interview that when he would call her ‘Shi’, she’d interrupt him saying, ‘I’m John’.

Now the whole family address her as John (so we will too), and at her mum’s Unbroken film premiere, she wore a suit and tie to match her older brothers Pax and Maddox. Back in 2010, Jolie told Vanity Fair: “She wants to be a boy. So we had to cut her hair. She likes to wear boys’ everything. She thinks she’s one of the brothers.”

For many parents, behaviour like this can be a bit of a minefield. Of course, lots of girls like the same toys, clothes and games as boys. But what about when a child seems to 'want to be' a member of the opposite sex? Does this hint at gender dysphoria, or identity issues? Or is it just a natural part of growing up?