A woman in Belgium became the world’s first to give birth to a baby using her transplanted ovarian tissue that was frozen when she was a child, according to new research published in Human Reproduction on Wednesday. The 27-year-old, unidentified woman had an ovary removed at age 13, when she began receiving invasive treatment for sickle cell anemia. Her other ovary failed following the treatment, which meant she would have been unlikely to conceive without the transplant. The woman gave birth to a healthy boy in November 2014. Doctors hope the procedure could eventually help other young patients at risk of ovarian failure.