Dr Andrew Holton an epilepsy doctor at the Leicester Royal Infirmary in 2001 who wrongly diagnosed hundreds of children and was suspended is challenging a decision ordering him to retrain.
The charges are that Dr Holton gave wrong diagnoses of epilepsy to 618 children in Leicestershire between 1990 and 2001.
In January the General Medical Council ruled that his performance was "seriously deficient" and imposed conditions on his practice.
"I am slightly stunned - we understood that not many conditions were put on him - and he was virtually free to continue his retraining and go back into the wide world. We will go to the appeal hearing and put forward our views. Other parents are equally stunned - they thought they could get on with their lives, but the battle goes on." said Trevor Parr, father of a boy who was misdiagnosed.
General Medical Council's fitness-to-practise panel said: "Having found that the standard of your professional performance has been seriously deficient, the panel considered whether it is sufficient to direct that your registration should be subject to conditions. It decided that conditions are sufficient and necessary for the protection of the public and are proportionate."
The doctor has challenged the decision and appealed against it.