One of the most popular provisions of the Affordable Care Act, or “Obamacare,” is the one allowing adult children to be added or kept on their parents’ health insurance plans until they turn 26. As a result of the change, 7.2 percent more 19- to 25-year-olds are now insured, and 6 percent more report being in excellent physical health.

But the benefit comes with a major downside: Though these individuals are often well into independent, adult life in other ways, it’s often their parents who receive their EOBs by default.

The loophole is especially concerning for women, who might have different reproductive health views than their policyholder parents. In 2013, 45 percent of women aged 18 to 25 were covered on a parent’s plan, according to a survey by the Kaiser Family Foundation.

Views on Privacy and EOBs Among Young Women

The same survey found that though the vast majority (71 percent) of young women say health privacy is important to them, only 37 percent knew that insurers commonly send EOBs to parents.

The knowledge that parents might see their medical documents can have a kind of chilling effect. Rebecca Steelman, a 21-year-old who lives in Seattle, said she felt compelled to call her parents in California to inform them that an intrauterine device would soon be popping up on an upcoming EOB. They were supportive, but Steelman says some of her friends haven’t been as lucky.

“I have friends who are scared to have that conversation, so they'll just pay out of pocket or not do the procedure entirely,” she said. “They're waiting until they're off their parents’ insurance or they're not going to do it at all.”

The disclosures to parents can extend beyond EOBs, too, in the form of denied claims, marketing materials, or surveys that innocently ask, “How was your experience at Dr. Psychiatrist’s office?”

Alina Salganicoff, director of women’s health policy at the Kaiser Family Foundation, said that the non-medical details on paperwork are often enough to determine what kind of provider the person visited, which is particularly an issue with “reproductive health services, mental health services, that other services that this group may want to keep private.”

While young adults can ask that their EOBs and other documents be sent to their own addresses, there’s no requirement that health plans accept or honor the request, according to Amy Moy, vice president of public affairs at the California Family Health Council.

Last year, California became the first in the country to mandate that health plans honor such “confidential communication requests” through a state measure that the Health Council co-sponsored. Moy said she hopes that the California law will spur insurers to extend the same privacy protections to young adults in other states.

Another issue, of course, is that many young people don’t know their parents might be receiving their EOBs—because they don’t know what EOBs are. Only about 12 percent of adults have proficient “healthcare literacy,” meaning they understand common insurance terminology.

“A lot of people are not aware that their personal info is being shared if they use their insurance,” Moy said. “For example, I know one college student in Michigan who had a pregnancy scare. Months later, she got a call from her mother like, ‘What is this? I didn't even know you were doing such and such.’ So one of the things we're working on is just letting people know about it.”