The 12-year-old schoolgirl and her 13-year-old boyfriend are believed to have become Britain's youngest parents.
She became pregnant at the age of 11 and gave birth to a girl weighing 7lb 4oz on Sunday. Being 12 years and three months old makes her five months younger than the previous youngest mother, Tressa Middleton, who gave birth in Edinburgh in 2006, according to The Sun.
A source told the newspaper: "The baby's mum and dad have been in a relationship for more than a year, so this isn't a fleeting romance. They intend to stick together and bring their daughter up together.
"They're very into each other, totally in love. She's in Year 7, he's in Year 9 at a different school."
April Webster and Nathan Fishbourne, the previous youngest parents, were 14 when their son Jamie was born in Caerphilly, South Wales, in 2010.
The new mother was 10 when she met her boyfriend. The pair, from north London, cannot be named for legal reasons. The schoolgirl lives with her mother, who is 27, and is supportive of the couple.
Yesterday, the new mother went to a register office to register the birth with her own mother and another woman.
The man claiming to be the girl's father rang radio station LBC. Presenter Nick Ferrari said the station would have to take his word for it, and they would call him Greg, which was not his real name.
The caller agreed he was supportive and right behind the couple, saying: "Unfortunately we found out the situation a month ago. That's from people making statements about 'allowing it to go on'. We didn't allow anything to go on at all, we didn't know this was happening.
"Unfortunately, kids this age are going to grow up to have boyfriends and partners or whatever. If they do things behind their parents' back that's something we're never going to be able to find out.
"We only found that she was actually pregnant a month ago. For us, what can you do? She was eight months pregnant. The baby is going to come into the world no matter what."
He agreed it was "heartbreaking", adding: "But you can't turn back time, you can only go forwards."
He said he comes from a working background.
"It's not as if we're all scrounging off the social like other people are suggesting. I work, I own my own business, and I'm fully going to support them with my own money, not necessarily forking out of other people's pockets. We're not scroungers. I will sit there and support this baby as best I can, with my own money, that I earn from working."
Asked his view of the 13-year-old boy, he said: "He's a great kid. Fortunately, they've been very supportive as well. We've had a discussion with his parents and everybody's... We've obviously come to the conclusion when you've got no other conclusion is 'What's happened has happened'.
"All we can now do is look to go forward in bringing this baby into the world without this bickering everybody is doing."
Asked if he believed in shame, he said: "No. Shame's not nothing. That little girl does not bring shame to me at all, I'm so proud of her. Shame doesn't even come into it."
He said it was "absolute nonsense" that the youngsters want to marry.
"That was news to us. We only see that again last night, when we found out all this information was coming out."
Hilary Pannack, chief executive of teenage pregnancy charity Straight Talking, said: "I know girls who've been pregnant at 13 and have had the baby, and I've heard of 12-year-olds before.
"It costs £100,000 to the taxpayer to support the average teenage mother in the first five years - it is a reason but is not the primary reason to stop teenage pregnancy, which is that we are talking about young people's lives.
"We need to stop the cycle of teenage parents having children who are more likely to become teenage parents themselves."