The plaintiff, surnamed Lo, divorced her husband in 1990 and raised their two sons on her own.

Worried that nobody would look after her when she got old, Lo signed the contracts with her sons after they both turned 20, stipulating that they must pay her 60% of the net profit from their incomes.

The supreme court said the contract was valid as Chu was an adult when he signed it, and that as a dentist he was capable of repaying his mother. It ordered him to pay Tw$22.33m ($744,000).