Two Florida college students say they were forced to submit to vaginal probes as part of a medical training program and were threatened with blacklisting if they declined.

A federal lawsuit against Florida’s Valencia State College claims the school would “browbeat” students who did not consent to the exams, threatening to lower their grades and blacklist them in the medical community.

The plaintiffs, who were not identified, enrolled in Valencia’s competitive medical diagnostic sonography program in 2013. The suit says that a second-year student who was nicknamed the “TransVag Queen” explained to them that students should undergo transvaginal ultrasound procedures to become better sonography technicians.

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“During orientation, the clients were told that these were voluntary procedures. However, as time went on, it became very clear that they were not voluntary,” Christopher Dillingham, a civil rights attorney in Winter Park, Florida, told NBC News.

The students allege they had to have the procedures done regularly, including by a male student, and then by other students in the program — even though there were anatomically correct simulators on which they could practice. Students also had clinical practice at hospitals, where they performed the same procedures on actual patients.

When the students expressed concerns to program chair Barbara Ball, she told them “they could find another school if they did not wish to be probed,” the suit says.

The students had no privacy, the suit goes on to say, claiming they had to take their clothes off in a restroom and then walk across the classroom to the sonography stations with a towel draped over them. Once they got to the stations, the situation only got worse, it said.

“In some cases, the student would have to sexually ‘stimulate’ Plaintiffs in order to facilitate inserting the probe into Plaintiffs’ vaginas. Plaintiffs experienced discomfort and embarrassment each time they had to endure this forced probing of their sexual organs,” the lawsuit claims.

But the students claim they were told they needed to participate.

“The college’s instructors retaliated against them by saying they would reduce their grades, they would blacklist them within the medical community, and they would not be able to get a job,” Dillingham said.

Valencia, which serves nearly 70,000 students across its five campuses, said it had not been served the lawsuit yet and therefore couldn’t comment on the specific allegations, but said it was reviewing the sonography procedure practices in its classrooms.

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“The use of volunteers—including fellow students—for medical sonography training is a nationally accepted practice. Valencia’s sonography program has upheld the highest standards with respect to ultrasound scanning for educational purposes, including voluntary participation and professional supervision by faculty in a controlled laboratory setting,” the college said in a statement. “Nonetheless, we continue to review this practice and others to ensure that they are effective and appropriate for the learning environment.”

Various researchers have studied peer physical examination among medical students. A 2012 study on first-year medical students’ willingness to participate in such exams found that attitudes depended on what region of the body was being studied: “Low-sensitivity examinations,” such as hands or the head, were generally accepted, but there were differences depending on the gender of the student and the gender of the examination partner.

The lawsuit was filed Thursday in Orlando, but Dillingham did not have the exact date the college would be served. The students are seeking tuition and textbook reimbursement and unspecified damages and are suing for being deprived of liberty rights, including their First Amendment right to “voice disapproval” of the coerced probes.

The three instructors named in the lawsuit did not return requests for comment from NBC News.

This story originally appeared on NBC News