Even with two wombs, she might not be able to conceive, Karlie Wilson was told when she was only 13.
But six years after it was discovered that she had a double womb she has defied doctors' predictions by giving birth to a healthy baby boy.
Mason James was born four days early on September 6 by caesarean section weighing 6lb 9oz.
Wilson, now 19, said: "I cried for three days when he was born, out of sheer happiness. My boy really is a miracle.
"I thought I was never going to have a child, but I've proved the doctors wrong."
Her problems began when she reached puberty and started to suffer crippling stomach pains.
Doctors at first diagnosed severe period pains but then discovered a ruptured cyst on one of her ovaries and carried out an operation to remove it.
A fallopian tube also had to be removed as part of the operation. But the pain continued and a scan showed that she had the rare condition Uterus Didelphus, or a double womb.
Blood from one of the wombs had been leaking and was collecting near Miss Wilson's pelvis, leaving the teenager in agony.
To stop the bleeding surgeons gave her injections that brought on a temporary menopause. They then carried out a hysterectomy to remove the faulty womb.
After the operation in 2001, doctors told Miss Wilson that although she had one healthy womb, her condition had seriously affected her fertility and that her chances of becoming pregnant were slim.
They said that if she did become pregnant, the foetus would almost certainly not survive in the womb past 20 weeks.
Miss Wilson, from Chelmsley Wood in Solihull, West Midlands, surprised doctors by becoming pregnant in January, eight months after meeting her boyfriend Oliver Mather-Price via the internet.
She then faced an anxious wait.
"The doctors had said I would only carry for 20 weeks," she said.
"When that date passed, I was so relieved. I had been convinced I would lose my baby. From then on, as every single day went by, I became more and more relaxed."
And now she is relieved.
1.In the womb, the baby's body is covered by a thin layer of hair but as soon as the baby is born it disappears.
2. The largest cell in the female human body is the ovum or egg present in the ovaries Pregnancy