Nathan is a Singaporean of Indian Tamil descent; his childhood was spent with his three older sisters and parents, V. Sellapan and Apiram, in Muar, Johor, in a house overlooking the sea. His father had been posted to the Malayan town as a lawyer's clerk for a firm that serviced rubber plantations, but the rubber slump of the 1930s sent the family's fortunes crashing. Nathan's father accrued debts, and eventually lost his job.