Pasqualino Cornelio began paying child support in 1998, after separating from and eventually divorcing his wife Anciolina. The twins were 6 years old at the time, the Toronto Star said.
After learning the children weren't his, Cornelio petitioned for a refund of the child support payments and a release from further payments, the National Post said.
However, Justice Katherine van Rensburg wrote in her ruling while he may have suffered a "moral wrong," he was still responsible for the children, the Post said.
"Mr. Cornelio was the only father the twins knew during the course of the marriage," the ruling said. "The relationship that developed from the time of their birth was the natural relationship between a parent and his children."
The twins' mother testified because of medication she was taking at the time, she has no memory of who the father might have been.