What the bloody hell? A four year old can't make that decision. A sex change is not just a snip snip job, it requires a lifetime of follow up surgeries and hormone treatments.
This is more like some mentally messed up hipster parents wanting to have something to brag to their hipster friends about with their token trans child.
When I was four, I wanted to be a Ninja Turtle.
Glad my parents didn't listen to me.