For many, an important marker of adulthood is forming a family, whether it’s having a child, getting married or cohabiting with a romantic partner. Researchers at Bowling Green State University’s National Center for Family and Marriage Research’s (NCFMR) say a majority (61%) of young adults have formed a family by age 25.

According to the research, over two-thirds of women (69%) have formed a family in early adulthood compared to just over half of men (53%). Education also plays an integral part in how a family is formed, in sometimes unexpected ways. Family formation in early adulthood was most prevalent among young adults with a GED diploma, at 81%. Those with at least a bachelor’s degree were least likely to form a family before age 25 (44%).

“Increasingly, young adults are spending more time in school as they pursue college and advanced degrees,” said Dr. Susan Brown, co-director of the NCFMR and a professor of sociology. “This tends to delay family formation—whether childbearing, cohabitation, or marriage—as most people aim to achieve financial security prior to starting a family.”

Researchers found the most common family formation experience was cohabitation, but with considerable variation. Thirty-seven percent of young adults with cohabitation experience have only lived with their significant other. One-half have cohabited and had a child, 36% have lived together and married, and nearly a quarter have experienced parenthood, marriage and cohabitation. Of those who cohabited and had a child, the majority first lived together, then became parents.

“Today, most marriages are preceded by cohabitation,” Brown said. “It’s really become a stage in the courtship process. It’s unusual for couples to marry without first cohabiting.”