Children questioning their gender are "unhelpfully" offered support to implement permanently what are "generally passing phases of growing up", a peer has said.
Lord Singh of Wimbledon said that, as a Sikh, he is appalled by the emphasis on sexual relationships and sexual identity at school.
Parents and teachers should have the right to opt out of such teachings, the crossbench peer added.
Lord Singh made his remarks as peers considered the Conscientious Objection (Medical Activities) Bill at second reading, which would reaffirm protections for healthcare workers who do not want to carry out certain procedures, such as abortion.
Lord Singh told the Lords: "This need to respect conscience occurs beyond the field of medicine.
'Young children are led to question their gender'
"Yesterday I was invited by the [Department for Education] to give a Sikh perspective on relationship teaching in schools.
"As a Sikh, I am appalled at the undue emphasis on sexual relationships and sexual identity currently being taught in school.
"Young children are led to questioning their gender and, unhelpfully, offered support to make permanent their potential differences – generally passing phases of growing up.
"Parents and teachers should have a right to question or opt out of such teachings."