A schoolboy has started the new term as a girl, after changing sex during the summer holidays.
The 12-year-old, from Sussex, attended school in a dress with long hair in pigtails, according to The Sun.
His name had also been changed to a female one by deed poll and it is believed he is preparing for sex-swap surgery.
Teachers at the secondary school were forced to hold an emergency assembly to break the news to other pupils.
However angry parents criticised the way the situation was handled and said their children were upset and confused by the announcement.
They said failure to inform parents in advance so they could explain what was happening to their children, had left the boy open to bullying.
One mother told The Sun: "They behaved appallingly by throwing this hand grenade into the room and then leaving the inevitable questions about it for unprepared parents."
However the boy's mother said she was trying to protect her child and act in his best interests.
It is believed the boy changed his sex during the summer holidays just before starting secondary school.
But former primary school classmates recognised him and the news spread.
The boy has been given a separate toilet and changing room in the sports hall.
Pupils were also told in the assembly to treat him as a girl and use his new name.
But the angry mother who spoke to The Sun said her daughter had told her the boy was already a target for bullying.
She said parents should have been sent a letter from the school first rather than staff breaking the news to children in the way they did.
She added they felt they had a right to know when their children were being confronted with a sensitive issue.
She said: "They were simply told, 'You may notice one pupil is not present in this assembly - that is because the pupil is now a girl.'
"Kids are by nature immature and insensitive. It is not fair either for the child who is undergoing this change. The girl, as she now is, will go through hell because of how this has been handled."
The boy has not returned to school since the assembly.
But according to The Sun, the school said the boy has not returned since the assembly because his parents were worried about his safety.
But they were assured that the boy would be coming back.
It is believed the headteacher at the boy's primary school had insisted he was treated as a boy.
A local education authority spokesman said: "When gender issues arise they are always handled very sensitively by our schools in full consultation with experts in this field and in liaison with families at what must be a very difficult period. The aim is to ensure that young people's education and general school life continues uninterrupted.
"We would urge the media to respect these sensitivities and handle these with respect for the children and families involved."