The Sheffield Hallam politician is at the centre of a sexism and homophobia scandal after making derogatory comments about women and gay men online more than a decade ago.
Mr O'Mara resigned from his position on the Commons' women and equalities committee on Monday but refused to go as an MP despite calls for Labour to remove the whip.
He has instead pledged to stay and even go one step further by fighting prejudice in society after being challenged to prove his worth by women's rights campaigners.
The MP said: "In terms of resigning as an MP? I think there’s a place for me.
"I want to educate people and help people going through those prejudices grow out of them. I’ve gone on that journey and feel I can help."
Comments made by the MP when aged in his early 20s appeared on the Guido Fawkes political commentary website yesterday.
The site alleged that in a comment posted on the Drowned in Sound music website in 2004, Mr O’Mara said: “Girls Aloud – I advise you to sack Sarah and the remaining four members (Nicola, Cheryl, Nadine and Kimberley) come have an orgy with me.”
In March 2004 on the same forum, he suggested Pop Idol’s 2003 victor Michelle McManus “only won because she was fat" and allegedly made homophobic and other misogynistic comments.
He is also said to have suggested it would be funny if jazz star Jamie Cullum was "sodomised with his own piano."
And the row deepened today as he was also forced to deny claims by 25-year-old bar worker Sophie Evans that he called her an "ugly bi**h" during a row at a Sheffield pub just months before he was elected to Nick Clegg's Hallam seat.
Since the scandal broke, members of the public have taken to social media to call for him to resign, while a number of politicians have also criticised his conduct.
Conservative MP Sarah Wollaston said O’Mara should be suspended from the party, while Liberal Democrat peer and former leader of Sheffield Council Paul Scriven, said: "It seems like a nasty pattern of sexist language and misogyny is developing from the Labour MP for Sheffield Hallam."
But shadow education secretary Angela Rayner said he should be given a chance to prove that he has changed.
She said: "He recognised those views were absolutely abhorrent and wrong and he changed those views."
The Sheffield branch of the Women’s Equality Party has also challenged him to make good on his words to campaign against sexism.
Charlotte Mead, Sheffield branch leader of the party, said “Actions speak louder than words. If he is to convince his constituents that he genuine the he will need to take action to improve the lives of women in Sheffield.
“He could show his support for the launch of Sheffield’s Safer Streets campaign later this month, campaign for funding for the threatened South Yorkshire Women’s Aid, or put forward a bill in Parliament seeking affordable childcare.
"Then people might begin to believe his commitment to countering misogyny."
Mr O'Mara yesterday issued a statement apologising for the remarks which he said were "offensive and unacceptable."
Today he said it was "important to take ownership of the things you’ve done wrong" and added: "Overwhelmingly people accepted my apology, accepted my sincerity and remorse, they accepted I have been through a journey of education."