A family court judge has ruled that a five-year-old boy must be taken from the care of his disabled mother, but dismissed a suggestion of "social engineering".
Judge Antony Hughes said the woman's disability made it impossible for her to meet her disabled son's needs by herself, and the level of local authority support she would need would be too extensive.
Detail of the case emerged in a ruling by the judge following a private family court hearing in Milton Keynes, Buckinghamshire.
The judge, who said the boy could not be identified, said Buckinghamshire County Council wanted to take the youngster into care.
He ruled in the local authority's favour, approved a care plan and said the boy needed a "permanent substitute family".
Judge Hughes indicated that the suggestion of "social engineering" had been made when a social worker involved with the boy had had given evidence during the hearing and been questioned by a lawyer representing the boy's mother.
"(The mother's) own disability renders it impossible, particularly over time, to meet (the boy's) developing needs," said the judge.
"One of the major issues in this case has been to the extent to which it would be possible for the local authority in providing support to the mother to care for (the boy) could effectively make up for her deficits and for (the boy) in that way to be provided with good enough parenting.
"It has been suggested that to remove (the boy) from his mother's care and provide an optimum level of parenting by adopters or long-term foster carers is in effect a feature of social engineering.
"I reject that proposition. The level of support that would be required in relation to such an arrangement would be so extensive as to be detrimental to (the boy's) welfare."
Judge Hughes said the boy had a number of health problems - including "global development delay" - and functioned at the level of a child half his age.
He said the boy's mother had a "learning difficulty".
The boy's father had been accused of a child sex offence, did not live at the family home and had been ruled out as a possible carer.
Judge Hughes acknowledged the "evident love" both parents had for their son and the "tremendous efforts" the mother had made.