Harvard School of Public Health researchers recently found that one in ten children whose activity choices and interests differ from typical gender norms have a higher risk of being sexually, physically, or psychologically abused, and of suffering from post-traumatic stress disorder, as children or later in life.

“The message needs to go to parents that they need to find ways that they can protect and support their children if they’re gender nonconforming because the discrimination and abuse that these kids experience has lasting impacts on their health,” said lead author Andrea L. Roberts, a research associate in the Department of Society, Human Development, and Health at the School of Public Health.

“Schools also need to teach tolerance and work hard to prevent bullying,” she said.

According to Roberts, past research has suggested that people are uncomfortable with gender nonconformity and may discriminate against those who fall outside of gender norms. Parents may become harsher in an attempt to change their children’s behavior to better conform to gender stereotypes.

Nearly 9,000 young adults answered a questionnaire in which they self-reported their childhood behavior and interests.

The questionnaire asked participants—whose average age was 22—to recall their experiences from before age 11, including favorite toys and games, roles they took while playing, and television or movie characters they admired or imitated.

They also answered questions about physical, sexual, or emotional abuse that they may have experienced throughout the course of their lives, and were screened for PTSD.

Roberts said that children who are considered “unusual”—including children who are disabled—are often targeted by sexual predators. Children who are gender nonconforming may also be at risk, she said.

Despite common assumptions about gender nonconformity in childhood, 85 percent of the children who were gender nonconforming identified as heterosexual as adults.

Men and women who ranked in the top 10th percentile of childhood gender nonconformity reported a higher prevalence of abuse compared with those who ranked below the median of nonconformity. Young adults who were gender nonconforming in childhood faced nearly twice the risk rate of PTSD than those who followed the norms of gender expression.

Victor G. Carrion, an associate professor at the Stanford School of Medicine, wrote in an email, “beyond screening for adverse childhood experiences, the pediatric and mental health community need to engage in policy and legislation that protects these children and educate their parents.”

Carrion acknowledged that regardless of sexual orientation or role identity, children are also vulnerable during periods in which they are exploring their identities if they do not conform to societal expectations.

“The message is tolerance, protection, and support,” Roberts said.

The nationwide study’s results were published on Monday in an online edition of Pediatrics, a research journal.

—Staff writer Cynthia W. Shih can be reached at cshih@college.harvard.edu.