The women were repeatedly beaten and raped by their father, enduring 18 pregnancies between them during the horrific ordeal. In November 2008 he was jailed for life.
On the publication of the Executive Summary of a Serious Case Review, authorities today apologised for a "collective failure" that left the women in his hands for several decades.
The review said the family had contact with 28 different agencies and 100 members of staff over 35 years.
The review, which covers a 35-year period, showed the family moved repeatedly - 67 times - in the Sheffield and Lincolnshire areas so the father could avoid detection.
Concerns were raised the women were bearing his children, but professionals failed to help them, the report revealed.
Today, Sheffield and Lincolnshire safeguarding children boards apologised for their failings and insisted changes had been made to protect families from abuse.
Chris Cook, independent chair of Lincolnshire Safeguarding Children Board, said: "We are genuinely sorry. We should have protected you.
"People's lives were devastated both by a controlling, power-obsessed and deviant father and our failure to act."
Sue Fiennes, independent chair of Sheffield Safeguarding Children Board, said they had failed the family and "nothing should shield us from that fact".
She said lessons were being learned by the agencies to make sure nothing similar ever happened again.
In November, Sheffield Crown Court heard the man's campaign of abuse started when the women were aged between eight and 10.
If they refused his advances, they would be punched, kicked and sometimes held to the flames of a gas fire.
The defendant, who called himself the "gaffer", took pleasure in fathering children by his daughters and would continue to rape them despite problems with their pregnancies, the court heard.
Judge Alan Goldsack QC said questions would inevitably be asked as to what professionals had "been doing for the last 20 years".
And after the case, the women's brother blamed social services for not protecting the family.
The Executive Summary of the review made 128 recommendations, including eight national recommendations.
Author Professor Pat Cantrill today said: "We have got to learn from these serious case reviews.
"You are aware, as I am aware, that there are a number of these serious case reviews that happen and we always don't seem to learn from them."
Recommendations include improvements in sharing information and record keeping.
Prof Cantrill said: "It only really needed one person with tenacity to keep pushing this and pushing this and we might have had a much earlier recognition and action being taken.
"There were people in the community that came forward and attempted to get the agencies to react in relation to this family and they were not listened to the way that they should."
She said a culture of "having a quiet word" had developed, with some professionals not knowing how to handle the situation.
"There was a real lack of grabbing hold of this situation and really being able to lead on it," she added.
Today, authorities confirmed nobody involved with the family had been sacked, disciplined or resigned over the failures.
Dr Sonia Sharp, executive director of Children and Young People's Services at Sheffield City Council, said: "What is very clear in this case is there is not a single big omission or big act that we can say 'Yes, it was that person'.
"What we can see, systematically, is time after time after time there were groups of people that failed to take action."
The summary divided the family's experiences into three episodes: their time in Sheffield from 1975 to 1988; Lincolnshire from 1988 to 2004; and Sheffield from 2004 to 2008.
In the first period, six referrals were made about the children between 1975 and 1978 alleging neglect and physical abuse, but there was no indication any agency was aware of factors to suggest the girls were being abused.
Between 1990 and 1996, either one daughter or the other was pregnant every year, sometimes twice a year, and on four occasions they were pregnant at the same time, it said.
It said professionals were suspicious the man was fathering his daughters' children and there were seven allegations reported about incest or sexual abuse from family members.
On 23 occasions from 1998 to 2005 the girls were specifically asked about the paternity of their children by various people.
But despite concerns, professionals felt there was nothing they could do unless the women admitted it themselves.
Police were finally handed a statement in 2008, after the family returned to Sheffield, and the man was arrested and prosecuted.
Ms Fiennes said: "It was plainly unrealistic to expect victims in these harrowing circumstances to disclose what has happened to them.
"There was collective failure, we all failed this family."
But she said she was confident things would be different today.
The NSPCC today also apologised for not meeting its "high standards" at the time.
A spokesman said: "Having reviewed the records, we have concluded that our practice in this case was not unusual for professionals at the time.
"However, it did not meet the NSPCC's high standards even then and we regret and apologise unreservedly for this.
"Since the 1970s, the way such cases are handled has moved on considerably."
