The children died from the human form of mad cow disease after being injected with growth hormones taken from human corpses, the BBC reported Wednesday.

Prosecutors said the corpses came from hospitals that specialized in infectious diseases and neurological disorders and might have been infected with Creutzfeldt-Jakob disease, the human variant of mad cow disease.

The first child given the growth hormones died of CJD 16 years ago.

French prosecutors charge the seven on trial failed to follow safety rules and hid the dangers of the treatment from the parents of the children.

Fourteen countries, including Britain and the United States, banned the extraction of pituitary gland hormones in the early 1980s, the BBC said, however, the practice continued in France until 1988.

Trial of the seven was expected to last four months. If convicted, the defendants face up to 10 years in jail.