When most Australians think about inheritance, they picture an estate divided equally among children, or perhaps the eldest taking the lion’s share, thanks to the centuries-old tradition of primogeniture. But what if the youngest child were the favoured heir? This lesser-known practice, called ultimogeniture, has quietly shaped family fortunes in parts of Europe—and it’s resurfacing in modern discussions about fairness, family dynamics, and estate planning.
Ultimogeniture is the inheritance custom where the youngest child—rather than the eldest or all siblings equally—receives the family estate. Unlike primogeniture, which bolstered dynasties and preserved large estates by favouring firstborn sons, ultimogeniture historically thrived in agricultural societies where the youngest child, often the last to leave home, remained to care for aging parents and maintain the property.
While ultimogeniture isn’t enshrined in Australian law, its underlying logic—rewarding the child who shoulders the greatest care burden—echoes in some contemporary estate plans. Families with farms or small businesses sometimes favour the child most involved in day-to-day operations, regardless of age. In 2025, with family structures more diverse than ever and debates raging about fairness and duty, the concept is gaining new attention among estate lawyers and financial planners.
Recent data from the Australian Bureau of Statistics (2025) shows a surge in family-led agricultural succession planning, with more than 40% of family farms considering non-equal inheritance arrangements. Legal experts note that parents increasingly tailor wills to reflect caregiving contributions, sometimes favouring the youngest if they remain at home or take over family responsibilities.
With Australia’s largest ever wealth transfer underway—over $3.5 trillion expected to change hands by 2050—the mechanics of who inherits, and why, are under the microscope. While most Australians still favour equal division, the rise in complex family dynamics, blended households, and caregiving responsibilities is prompting a re-examination of old norms.
Ultimogeniture may not be coming to the statute books, but its spirit is alive in the way families negotiate succession, particularly for assets like businesses, farms, or homes that demand ongoing stewardship. As social attitudes evolve and policies shift, especially with 2025’s focus on succession planning reforms and tax incentives for family-owned enterprises, expect to see more bespoke inheritance plans that borrow from historic customs like ultimogeniture—even if the legal system remains neutral on birth order.
Ultimogeniture might sound like a relic of the past, but its legacy is more relevant than ever as Australian families navigate the tricky territory of inheritance and fairness. Whether you’re passing down a family business, a farm, or simply want to recognise the contributions of your youngest child, understanding the lessons of ultimogeniture can help you create a will that stands the test of time—and family expectations.