Around 40 primary schools in England have introduced ‘gender neutral’ uniform policies that support boys wearing skirts.
The policy has been advocated by a lobby group which has received Government funding.
But a Christian group said the move towards schools encouraging transsexualism was concerning.
Campaign group Educate & Celebrate has received £200,000 from the Department for Education to provide equality and diversity training to school staff. It provides a sample gender neutral uniform policy on its website.
One of the schools involved, in Birmingham, said it aimed to promote “each child’s right to express their gender and personality in whichever way feels right for them”.
Andrea Williams, CEO of Christian Concern said: “Children at the age of five years old need to be reassured and supported if they experience feelings of confusion about their gender.
“The solution is not to encourage their confusion but to affirm their identity which is God-given.
“This policy will only serve to introduce unnecessary questioning and doubt to pupils who may have never otherwise experienced such feelings.”
Elly Barnes, who leads Educate & Celebrate, said around 40 primary schools and 40 secondary schools had introduced gender neutral uniform policies.
In Australia, the Government has proposed reforming a controversial state-funded LGBT education programme after serious concerns were raised.
The Government said parents should give their consent before their children participate in the lessons, and that the programme’s resources should not be used for “political advocacy”.
The Australian Christian Lobby welcomed what it called a ‘substantial pruning’, but said that teachers will still be encouraged to drop the pronouns “he” and “she” when referring to students.