Emirati student Shaima lives in Abu Dhabi with her four siblings and parents. But she says her seven-person household is small — her father grew up alongside 11 brothers and sisters in the days when the region’s families were legendarily large.

The generational downsizing in the 21-year-old’s family reflects a dramatic social shift across the United Arab Emirates: Emirati women bear about half the number of children their grandmothers did in 1970, with the fertility rate down from 6.7 per woman in 1970 to 3.7 by 2017, according to official data.

In a country that lures millions of migrant workers to power an economy that has grown at breakneck speed since the 1960s, the trend has prompted many Emiratis to worry that they belong to a dwindling minority in their own country — and spurred authorities to offer more support designed to encourage large families.