Debbie; forcing children to choose a label is deeply damaging
Children are male or female. That isn't a label, its a factual material description.
What it means to be a male or female child is gender eg a construct of society specific to time and place.
There needs to be space for male and females to be unencumbered by gender stereotypes/ sexism.
The healthiest response, is not to 'assume' the gender stereotypes/ label of the opposite sex especially when this involves surgical / medical interventions.