An MP appeared close to tears as she challenged those protesting against LGBT equality teaching, insisting: "We aren't going to get back in the closet."
Labour former minister Angela Eagle, who was the first openly gay female MP when she came out in 1997, said such education is not "propagandising" or about "trying to turn people gay", but about respecting their rights to have an "equal welcome in school" and not be bullied.
Ms Eagle's voice broke with emotion when speaking during a debate on parental involvement in teaching linked to the Equality Act 2010, called by a Labour colleague who has defended campaigners protesting against LGBT equality teaching at a Birmingham primary school.
Anderton Park has been at the centre of a series of school gate protests in recent months, leading to a court injunction banning demonstrations inside an exclusion zone around the site.
Roger Godsiff, Labour MP for Birmingham Hall Green which is home to the school that raised concerns about the level of consultation with parents.
He said those who protested "had some valid reasons for doing so", claiming the headteacher seemed "totally unwilling to have meetings with the parents to address their concerns and to seek a compromise way of resolving the conflict".
He described the protesters as "mostly young mothers", adding they have "done nothing wrong, other than be good mothers who want to express concerns about what their children are telling them".
Mr Godsiff, who was previously reprimanded by Labour's chief whip after backing the campaigners, concluded his speech with an apology for "any offence caused" by what he has said or written, including to members of the LGBT community in Birmingham and across the country.
He was also heckled throughout his speech by Labour colleagues and others.
Speaking in the Commons, Ms Eagle said of teaching sex and relationship education in schools: "If we had have done it generations ago there would have been an awful lot of much happier and well adjusted people than those that have been monstered in the way that they have for the way that they are in a system that was disfigured by the effects of section 28."
Ms Eagle added: "And yet here we are in the middle of a similar kind of moral scare which is being whipped up by people who have a different agenda to the well being of children and their adjustment to the facts and experience of 21st century life in the UK."
She became visibly upset and appeared close to tears as she spoke in the chamber, telling MPs: "We aren't going to get back in the closet or hide or be ashamed of the way we are and nor are we going to allow a generation of pupils that are now in school to go through what the pupils in the 80s had to go through because this chamber let them down and nor are we going to allow this to happen in the name of religion."
Labour former minister Chris Bryant spoke about progress made, but said: "We will fight - not physically of course, we'll do it probably with drag queens and feather boas, and all the stereotypes you can gather, and rugby players and football players, one day, please God, and we will fight to make sure this is not rolled back."
Opening the debate, Mr Godsiff said some aspects specific to teaching of sexuality were not popular with more socially "conservative" parents and also challenged allegations of "homophobic hatred" against the campaigners.
He also said: "I regret the controversies which have arisen around the two schools in Birmingham. I believe they could have been avoided if the schools had taught the provisions of the Equality Act in different ways and taken the parents' concerns into account.
"For my part, I apologise unreservedly for any offence caused to any person of whatever sexual orientation by anything I've said or written.
"In particular, I apologise unreservedly to members of the LGBT community in Birmingham and throughout the country for anything I may have said or written which has caused offence to them."
Education minister Nick Gibb said the Government had introduced the regulations for making relationships and sex education (RSE) compulsory in schools and was determined to press ahead with the policy.
The guidance he added had been "very carefully crafted and written in order to build the widest possible consensus for this policy".
Referring to the situation in Birmingham he said: "We are working very hard to try to assuage concerns if you like, but ultimately we will be on the side of the headteacher in making these decisions because we do believe that ultimately the content of the curriculum is a matter for schools."