Oluyinka Olutoye

Oluyinka Olutoye was born in Nigeria in 1966 and moved to the United States to study medicine, training first as a general surgeon before specialising in the surgery of children and, eventually, of patients who had not yet been born. Fetal surgery was still a young and controversial field: operating on a baby inside the uterus meant treating two patients, mother and child, at once, and risking a pregnancy to try to correct a defect months before delivery.

In 1999, while operating on a 21-week-old fetus to repair spina bifida, a photograph was taken of the tiny hand emerging from the incision and closing around Olutoye's finger. The image, later widely published, became one of the most recognisable in the history of fetal medicine, though for her the surgery itself, not the picture, was the point: correcting the defect early gave the child a far better chance of walking.

She went on to lead pioneering surgical teams, including one that successfully separated conjoined twins joined at the chest and abdomen, and helped develop techniques for operating on tumours and organ defects in fetuses still developing in the womb.

Now a professor of surgery and pediatrics, she has trained a generation of fetal surgeons and continues to argue that some conditions are better treated before a child is even born.