The child may grow up to realise they do have gender dysphoria there's just as good a chance the child could grow up to be a very happy boy. That's one of the reasons why I believe that children should be left out of the gender identity debate. Transitioning as an adult has been the hardest decision I've ever made and I understand all of the ramifications of it, I don't think a child can fully understand the extent of the path transition takes you on.
Many of the ways Gender Identity is explained to children reinforces harmful stereotypes - that you can't be a masculine woman, to look a certain way you have to actually be a man. It's not responsible to use a 'gender spectrum scale' to say man looks like this, woman looks like this and if you don't fit those you're neither. I know TRAs think it's inclusive of everyone but it's really not.
Conversely, gendered stereotypes are deep rooted in society and I know some parents (who have no experience with the trans community) being the worst cases of 'this is boy/girl stuff, you're not supposed to play with it' and are deeply uncomfortable when their child goes against the status quo.
It's hard to talk about non-conformity, as humans we want a place to fit in. If you're taught as a child that only girls are allowed to play with barbies, is a boy going to be able to tell his parent 'I'm a boy, I want to play with my Barbie' or is he going to think well I must be a girl then.
But really we just need to let kids be kids, support them in playing with/dressing in/doing what they like and leave the issue of gender identity until they're older.
Obviously it's much harder when your child comes to you and says they're trans - I'd personally advocate watchful waiting instead of transition but each family has to make their own decision based on what's in the best interest of the child.
Until someone's developed into adulthood (and even then there's no guarantee) I don't think they have the experience in critical thinking to challenge what they've been taught/distinguish between that and Gender Dysphoria.