New York University’s Langone Health received a federal grand jury subpoena from the Department of Justice seeking information about minor patients who received gender-affirming care, according to a statement posted on their website Monday evening.

This is the first known criminal probe by the Justice Department to obtain private medical data about transgender children receiving gender-affirming care, as the Trump administration escalates attacks on trans rights.

NYU Langone said in the statement that it received a subpoena on May 7, and that it was one of several medical institutions that had received grand jury subpoenas from the United States attorney for North Texas. The DOJ is also seeking the names of hospital employees who provided gender-affirming care.

The Trump administration has long tried to obtain medical records of trans youth, as have other state officials, including Texas, but this is the first known use of a grand jury.

NYU Langone notified parents of transgender youth aged 18 and under about the grand jury subpoena.