London - South African Tania Clarence admitted to killing her three young disabled children when she appeared in a UK court on Monday, the British Press Association reported.
The 42-year-old mother wept in the dock as she pleaded guilty to the manslaughter of Olivia, four, and three-year-old twins Ben and Max by diminished responsibility.
But Clarence, of London, denied murdering the three children between April 20 and 23, when she appeared at the Old Bailey.
Clarence was tearful as she entered her pleas in the dock as her husband Gary looked on.
A date was set for a three to four-week trial to start on February 21 next year.
The defendant was remanded to a secure mental hospital.
Police were called to the family's five-bedroom home in Thetford Road in the wealthy south-west London suburb of New Malden on April 22 where they discovered the children, who were pronounced dead at the scene.
All three of Clarence's children suffered from type two spinal muscular atrophy. Also known as floppy baby syndrome, the genetic condition leaves children with little control of their movements and can drastically shorten life expectancy.
Clarence was treated for cuts at St George's Hospital in Tooting, south London, and charged on April 24.
A further pre-trial hearing will take place on October 3. - Sapa