This was no usual divorce hearing; Gregory is the plaintiff. He is attempting to become the first American child to divorce his mother.
The boy's lawyers (acting without a fee) questioned Rachel Kingsley, 30, on her fitness to remain mother of the son she has looked after for less than 12 months in the past eight years. Gregory wants the court to end her rights as a parent and consent to his adoption by his foster family. After shuttling in and out of foster and children's homes, Gregory says he just 'wants a place to be'.
Ms Kingsley, who lives with her two other sons, aged eight and 10, argued yesterday that she had tried to give the three boys a good home. She had been forced to leave Gregory in foster homes because of her low wages as a waitress and the inadequacy of child welfare systems in the United States, especially in Florida.
She claimed she now had a stable home with her boyfriend and sons in St Louis. Gregory's lawyers produced evidence, however, that the boyfriend regularly beat her up, including once, in the presence of her sons, last month. Her own sister-in-law, Jeanette Glynne, tearfully told the court that Ms Kingsley was an unfit mother, who used drugs in front of her children. 'I wish someone would do something for the other two boys,' she said. 'Nothing is going to change. She keeps telling me her life is improved. But the pattern is the same.'
The case has attracted intense attention in the US. It was televised live by the Cable News Network (CNN) for several hours yesterday, displacing news of the presidential campaign. Both Gregory and his mother are negotiating with Hollywood for the film rights to their story.
In part, the interest has been aroused because the case echoes several of the themes raised in the presidential race: family values, welfare and working poverty.
Republicans have pointed to the case as the kind of anti-family, social engineering - children suing their parents - which would stalk the land if Bill Clinton became President. They point to an article written 20 years ago by Governor Clinton's wife Hillary, in which she says that, in certain extreme circumstances, children should have the right to sue abusive parents.
As it unfolded in court yesterday, however, Gregory's story demonstrated the difficulty of matching political slogans to the banal tragedies of the real world. Despite all the talk of family values in the Reagan-Bush era, child poverty has steadily grown in the US in the past 12 years. Almost 500,000 children now live in foster homes, a 50 per cent increase in 10 years.
Ms Kingsley was married at 17 and abandoned by her husband, with three sons, at the age of 21. She blames the inadequacy and bureaucracy of the state and national welfare systems for forcing her to place her children in homes, rather than supporting her in her own home. Gregory remembers things somewhat differently. 'My mom would go out and party all the time and leave me at home and stuff,' the boy told a television interviewer last week.
A Florida lawyer and his wife, George and Lizabeth Russ, found Gregory in a boy's home two years ago. They became his foster parents and Gregory asked them to adopt him. When Ms Kingsley objected, Mr Russ encouraged Gregory to bring the case against his mother. Her lawyers have said that the boy took a cynical decision to shop for a wealthier family.
Gregory disputes this. 'I think people think that I'm just doing this because my mom wouldn't give me a Nintendo,' he said last week. 'That's not why I'm doing it. I'm doing it so I can be happy.'