A mother, who pleaded guilty to starving her infant son to death, was ordered to plead not guilty by the District Court yesterday. Deputy Judge Adriana Tse criticised defence solicitor Benjamin Tao Tsz-kin for allowing his client, So Suk-yee, to plead guilty. A background report on So, 32, showed that she had denied starving the baby, the judge said. So fed the infant formula milk that was too diluted to keep it alive. The three-month-old boy weighed only 3kg when he died last year, half of what a normal baby that age should weigh, and had put on just 160 grams since birth. So's psychiatric report also suggested she might be mentally handicapped, the judge said yesterday. So was to be sentenced yesterday, after pleading guilty this month to one count of mistreating a child. The court had ordered various reports on her - psychiatric, psychological, background and social-welfare reports - in preparation for sentencing. Referring to one of the background reports, the judge said 'the defendant did not accept she had over-diluted the milk. The defendant is negating the whole prosecution case. The defendant cannot plead guilty if what she admits has departed from the admitted facts.' Tao insisted that So told him to enter a guilty plea on her behalf. But the judge noted: 'She [So] is now disputing the fact about the dilution of milk. She denies the entire basis of the admitted fact. I don't understand how you [the defence lawyer] can let her plead guilty.' According to one report, the mother had said the baby did not have a birth certificate, which prevented her getting medical help for it. The judge said: 'The failure to obtain a birth certificate did not kill the child. The prosecution case is about the question of starvation.' The judge ordered So's guilty plea to be reversed, and adjourned the case to next Tuesday in another court. The judge also said that there might be a need for a pre-trial review if there was a retrial. So remains remanded in custody. The defendant has two children, aged 10 and 12, with her former boyfriend, and a four-year-old daughter with her husband, from whom she is separated. Her fourth child, a boy aged two, and the victim were the children of her current boyfriend. The Social Welfare Department says it has arranged hostel services for the four-year-old and the two-year-old. The 12-year-old was living with a grandmother, and the 10-year-old had been placed in a children's shelter. A spokesman for the department said it would closely monitor the trial to provide appropriate support to the children. It would also keep close contact with the family in order to protect the welfare of the four children. The baby, who was not named in court due to the lack of a birth certificate, was eventually taken to Princess Margaret Hospital in Kwai Chung on May 5 last year, but died 90 minutes later, the court had earlier heard.