Children questioning their gender are "unhelpfully" offered support to permanently implement what are "generally passing phases of growing up", a peer has said.
Lord Singh of Wimbledon said as a Sikh he is appalled by the emphasis on sexual relationships and sexual identity in what youngsters are taught at school.
Parents and teachers should have the right to opt out of such teachings, the crossbench peer added.
Lord Singh's remarks came as peers considered the Conscientious Objection (Medical Activities) Bill at second reading, which is bidding to reaffirm protections for healthcare workers who do not want to carry out certain procedures - such as abortion.
He told the Lords: "This need to respect conscience occurs beyond the field of medicine.
"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."