A teacher has been reprimanded after she admitted making sexually offensive comments to a class of teenagers.

And she has been ordered to take down a poster in her classroom after an angry dad complained that it promotes homosexuality.

Bingley Grammar School has unreservedly apologised to parent Michael Waite after English teacher Yolande Armstrong made the remarks during a lesson attended by his 14-year-old twin daughters, Zoe and Gemma.

The comments were made during a class discussion about what it would be like to be in the womb.

Mr Waite, 39, of Cullingworth, complained to head teacher John Patterson after his daughters told him what Miss Armstrong had said.

"I was appalled by her comment and my daughters thought it was disgusting," said Mr Waite, whose stepdaughter Samantha, 15, also goes to the school.

"We're Mormons who are trying to bring our children up with high moral standards.

"We don't expect them to use language of that nature and send them to school expecting that to be continued there, only to find out that isn't the situation.''

In a letter to Mr Waite, pictured with his daughters, Mr Patterson said: "As a school we apologise unreservedly for the comments made by Miss Armstrong in your daughters' English lesson.

"For her part too Miss Armstrong apologises fully and is greatly upset by the offence she has caused.

"When I interviewed Miss Armstrong she gave a full and frank account of the incident, confirming what your daughters had reported.

"She explained the reference had originally been made by a boy in a poem written about the world of an unborn baby. It was in an ill-judged attempt to diffuse the tittering of this boy and his friends that she made the offensive remarks.

"I met Miss Armstrong and her union representative to discuss her remarks within the formal internal disciplinary framework that our governors have in place for teaching staff.''

In his letter Mr Patterson said he could not divulge what disciplinary action had been taken against Miss Armstrong but he added: "I hope that you will accept my assurance that the matter has been taken very seriously indeed and dealt with appropriately.''

A spokesman for Miss Armstrong's union, the National Association of Schoolmasters and Union of Women Teachers (NASUWT), refused to comment on the case.

The poster - jointly produced by the Northamptonshire Lesbian and Gay Alliance, Northamptonshire County Council, Northamptonshire Health Authority and Northamptonshire Police Authority - carries the message: "Lesbians and gay men are...daughters, sons, mothers, fathers, sisters, brothers, cousins, grandparents, uncles, aunts, in-laws, foster parents, adoptive parents, carers, friends, workmates...Lesbians and gay men are entitled to the same rights as any other Northamptonshire resident.''

Mr Waite said: "I'm not intolerant of people's rights to live their lives as they want but as a religion - and we're not unique in our beliefs - we don't go along with promoting homosexuality and teach our children the virtues of having a family unit based on sexual contact between a man and woman after marriage.''

Initially Mr Patterson advised Miss Armstrong to remove the poster as he thought it had put her in a difficult position but it remained in place.

After being contacted by the Telegraph & Argus, Mr Patterson said: "The poster attempts to promote tolerance of people of different sexual orientation just as another poster, displayed alongside, promotes tolerance of different races.

"Department for Education guidance makes clear that teachers should deal honestly and sensibly with sexual orientation and that schools should be able to deal with homophobic bullying.

"However we certainly do not wish to run the risk of giving offence to parents, nor do we wish to run the risk of giving any inappropriate or ambiguous messages to pupils. I have therefore instructed the member of staff to remove the poster."