A couple committed a "deplorable and terrible betrayal of trust" against their two adopted children they allowed to be abused by paedophiles, a judge said today.
Both girls told their parents about their ordeals but nothing was done to prevent future assaults.
The mother said she could not step in because one of the paedophiles "helped them with money and a car".
The husband and wife, aged 56 and 55, who live in the Trafford borough of Greater Manchester, were convicted of child cruelty.
The adoptive father was also found guilty in August of sexually abusing the elder girl over a six-year period.
Judge Jonathan Geake sentenced the husband to nine years in jail while his wife was jailed for five years at Manchester Minshull Street Crown Court.
Last year, paedophiles Colin Molloy and Sam Nelson were jailed after admitting a string of sexual offences involving the two youngsters, which started when they were as young as seven and 13.
Molloy, 46, admitted nine counts of raping the younger girl. while Nelson, 43, pleaded guilty to engaging in sexual activity with both girls.
The girls complained to their mother about the activities of Nelson and Molloy, while the father was made aware of Molloy.
Sentencing the pair, Judge Geake said: "This was a deplorable and total failure to protect those two girls from the risks posed.
"These were children adopted by you and because of their unfortunate start in life they were probably more vulnerable than other children.
"They were entitled to proper care and protection."
Both parents, who cannot be named for legal reasons, relied on babysitting, lifts home and, to some extent, cash from Molloy and Nelson, the judge continued.
"You were prepared to put your own practical convenience before their safety," he said.
"This was a a deplorable and terrible betrayal of trust. No one can know how much damage this has done to these two girls both physically and psychologically."
Following sentencing, Det Sgt Charlotte Whalley, of Trafford Public Protection Investigation Unit, said: "Even though these girls had the bravery to tell an adult what was happening to them, it was allowed to continue.
"Thankfully the girls were courageous enough to report the matter to the police and all the people involved have been prosecuted for their horrendous crimes.
"We take all reports of sexual abuse very seriously, including historical abuse. There will be a full investigation and support provided to the victim throughout the whole process."
During the couple's trial, the jury was played video police interviews of the younger girl, who initially raised the alarm by telling her teacher last January.
She said Nelson had been "doing rude stuff to her" at his flat as he minded her after school while both parents were at work.
"I kept on trying to push him away but he kept on doing it," she told officers.
Nelson also played pornographic videos on his computer in her presence and masturbated to them.
When she returned home she told her parents she had been assaulted and was sore.
"My dad said, 'if he is hurting you then don't go down there', but I said if no-one is in (at home) then I have no choice," she said.
"My mum said they could not do anything because he helped them out with money and a car."
Molloy raped her under her own roof but again her mother did nothing.
Social services became involved when the allegations were made and removed the children from their home, which was said not to be fit for habitation, unkempt and unsanitary.
The two girls are now in foster care elsewhere in the area.
The couple maintained their innocence, the court was told.
Ahmed Nadim, representing the father, said his client had poor health and asked for that to be taken into account on sentencing.
He has very limited mobility, diabetes, high blood pressure and osteoarthritis, he said.
Patrick Cassidy, for the mother, said psychological reports showed she had a "lengthy history of depression" over the last 30 years.
He said: "Her periodic agoraphobic tendencies combined with anxiety, panic attacks and insomnia all point to a defendant who had less capacity to respond and less culpability even because of the situation she had with her health."
He added she already recognised the consequences of the conviction after she was displaced from her home after news of the verdict spread on her estate.
She was forced to live in a hostel for the homeless following her release on bail pending sentencing.
Mr Cassidy said that the author of her pre-sentence report concluded there was a "degree of uncaringness" from her about the girls' exposure to the paedophiles but he said he and his legal team had witnessed clear signs of distress from her and it did not appear feigned.
He questioned whether both defendants with "plain difficulties in their own lives" would have found themselves in the dock if they had not been allowed to adopt in the first place.
Judge Geake said the couple had been deemed individually and collectively as suitable to adopt the girls separately but said the reality was that "neither of you was remotely suitable or trustworthy as a parent".
Following conviction, Manchester City Council, which conducted the adoption process, said a "full assessment and proper checks" were carried out.
Pauline Newman, the council's director of children's services, said: "After this terrible case came to light we asked for our actions at the time to be independently evaluated to ensure that the correct procedures were followed - which they were.
"The sad fact is that there will always be a small minority of people who wish to hurt the most vulnerable in our society.
"In terms of adoption, we carry out very thorough checks to minimise any risk to children and to ensure prospective parents are suitable.
"The adoption process is not easy and the procedure has become even more thorough since this couple went through it.
"The vast majority of adoptive parents want to provide the best possible family for children and young people - and do a fantastic job.
"This case must not detract from that fact."