The BBC's Paul Reynolds: "If the boy dies the charge will become one of murder"

A jury in Missouri convicted the man, Brian Stewart, of assault and recommended that he spend the rest of his life in prison. He is to be sentenced early next year.

Prosecutors alleged he intended to kill his son to avoid paying child support. The boy, who is now seven, was diagnosed with full-blown Aids in 1996.

Stewart sat impassively as verdict was read, reports Paul Reynolds

Stewart, 31, of Columbia, Illinois, was arrested in April. He was accused of using his position as a medical technician to steal tainted blood and then injecting it into his son while the boy was sick in hospital.

Boy's mother: Living with realisation he will die

Doctors contacted the police after they found the boy was infected with HIV and could not understand how he had contracted the virus.

Police say suspicion fell on Stewart when he told his girlfriend that she would never collect child support payments, because their child would not live that long.

The boy's mother said he needed extensive care and had been near death several times.

She said: "We live daily with the realisation that he will die of the disease or its complications."

However she said her son was trying to live as normal a life as possible, even going to school when he was able.