Some Americans may now prefer life without children, though most still report in surveys that they want two kids. Others may be struggling to have children, or can’t afford expensive fertility treatments.

Juggling work and family is a big factor. Census said women aged 40 to 50 years who were in managerial or professional occupations were more likely to be childless than women of similar age in other occupations.

With more women having their first child in their mid 30s, late 30s and early 40s, American families may be shrinking: The number of women aged 40 to 44 who had only one child roughly doubled between 1976 and 2014, Census said.