Forced sexual initiation, a first sexual intercourse that is forced or coerced, is a specific form of sexual violence recognized by the World Health Organization. A new study looks at data on forced sexual initiation — the numbers of women who report experiencing it, their demographic characteristics, and the associated gynecologic and general health outcomes — among American women.

The researchers analyzed data from over 13,000 women between the ages of 18 and 44. The women participated in the 2011-2017 National Survey of Family Growth, which was conducted by the Centers for Disease Control and Prevention. The data from the study predates the #metoo hashtag.

The women who reported forced sexual initiation were often very young, and their encounters were with men who were seven years older.

Forced sexual initiation was reported by 6.5 percent of respondents, the equivalent of 3.35 million women in the 18 to 44 age group nationwide. The average age of women who experienced forced sexual initiation was 15.6 and the average age of those who reported voluntary initiation was 17.4. The average age of the partner/assailant of women who reported forced sexual initiation was six years older than those of women who reported voluntary initiation — 27 years old, versus 21 years.

Compared to those whose sexual initiation was voluntary, women whose sexual initiation was forced were more likely to experience an unwanted first pregnancy or abortion. They were also more likely to suffer thereafter from endometriosis, pelvic inflammatory disease and problems with ovulation or menstruation.

The findings are alarming, Laura Hawks, lead author of the study, told TheDoctor. The women who reported forced sexual initiation were often very young, and their encounters were with men who were seven years older. “This represents a huge power discrepancy in terms of age, and usually in size.”

“Sexual violence is a manifestation of gender imbalance. Power differences between men and women in our society can contribute to high rates of sexual violence,” said Hawks, a research fellow at Cambridge Health Alliance and Harvard Medical School.

Parents can correct this imbalance by making sure they treat young boys and girls equally. “We need to give young girls as much time to talk as boys, and promote their interests, whatever those may be,” Hawks said.

As kids get older, it’s important for parents of both boys and girls to talk with their kids about sexual consent, and discuss how to negotiate a sexual encounter, said Hawks. While this may be a very uncomfortable conversation, it is also a necessary one, so seeking out guidance is an important thing to consider.

“What we really want to prevent is any instance where a sexual encounter is not consensual,” said Hawks. Some of the men who were considered assailants in this study might not have realized they were engaged in a non-consensual encounter, explained Hawks, but that does not make it consensual.

The team only looked at sexual violence against girls and women in this study, but she said it is also important to study violence against boys and men, and those who identify as trans or non-binary.

The study and a related editorial are published in JAMA Internal Medicine.