A photo of Shamima Begum is held by her sister.
The relative said Shakil had some "supervised contact" with her son, but he was not in her custody.
She said: "I applied to marry an English-speaking fighter between 20 and 25 years old". "We were just waiting for something to come out".
"The security minister, Ben Wallace, has said he would not put officials" lives at risk to rescue United Kingdom citizens who went to Syria and Iraq to join Islamic State.
"The caliphate is over".
Her family have said they understand some people would not want her to be allowed back into Britain, the Daily Express reports.
"Now all I want to do is come home to Britain", she said in an extraordinary interview with the Times of London.
The British authorities estimate around 900 Britons traveled to Syria and Iraq to join the conflict, of whom around 300-400 have since returned - and 40 have been prosecuted.
When Ms Begum left for Syria in 2015, IS had taken control of large tracts of northern Syria and northern Iraq.
"I'm scared that this baby's going to get sick in this camp".
On arriving in Raqqa, Ms Begum stayed at a house with other newly-arrived brides-to-be.
She said she should be giving birth "any day now". Within 10 days, she was married to a 27-year-old from the Netherlands.
Writing for The Guardian, he said: "Even (Ms Begum), as unrepentant as she may be, should be given a chance, if we are to stand by our values - and if we believe our society is strong enough to reabsorb a 15-year-old who went badly off the rails".
Arsene Wenger with a damning verdict on Manchester United and Alexis Sanchez
It wasn't just them who didn't seem to have their heads in the right place on a big night, but every United player seemed so. The Chilean was introduced to a crunch Champions League clash at Old Trafford shortly before half-time.
"It was like a normal life". The life that they show on the propaganda videos; it's a normal life.
"Every now and then there are bombs and stuff. But other than that".
"I was weak", she said. It was from a captured fighter seized on the battlefield, an enemy of Islam.
She added: "I know what everyone at home thinks of me as I have read all that was written about me online". Begum says the other two were alive as of two weeks ago.
Her daughter died at the age of one year and nine months and was buried in Baghuz a month ago.
She then paid a taxi driver to take her close to the Turkish border.
Social services would also certainly step in to consider whether her child should be removed to protect him or her from radicalisation. That's all I want right now.
Only those with dual nationality can have their citizenship revoked, as it is an offence in global law to leave someone stateless, said Helen Fenwick, professor of law at Durham university and an expert on counter-terrorism and human rights law.
If Ms Begum got out of the country, that is the kind of charge she could face - along with encouraging or supporting terrorism.
Mr Javid said: "We must remember that those who left Britain to join Daesh were full of hate for our country".
"If the woman was showing complete remorse, it would be completely different", he told BBC Radio 4's Today programme.
She added: "I never thought it would happen".
With the Islamic State's territory dwindling to nothing, more and more members, including females, are surrendering to anti-ISIS forces.