Douglas Kennedy, son of late Robert F. Kennedy, on trial for scuffle with hospital nurses

(CBS/AP) MOUNT KISCO, N.Y. - The son of the late Sen. Robert F. Kennedy went on trial Monday facing accusations that he twisted a nurse's arm and kicked another nurse to the floor as he tried to leave a suburban New York hospital with his newborn son.

Witness Anna Lane testified that the nurses tried to stop Douglas Kennedy when he tried to leave on Jan. 7, 2012 because there was no order for the baby's release "and I felt there was a security risk."

She said Kennedy told her he didn't need permission.

Kennedy is charged with harassment and child endangerment. He calls the charges absurd, saying that he was just taking his 2-day-old son, Anthony Kennedy, for some fresh air outside Northern Westchester Hospital.

But nurses testified that would have been very irregular. Angela Adamo said that when Kennedy approached the nurses' station with his request, she tried to dissuade him because it "didn't seem to make much sense to me."

She also testified that the baby, in a hat and blanket, wasn't appropriately dressed for a January evening.

Lane said Kennedy, with the baby cradled in his right arm, was not persuaded and moved to the elevator and stairwell where Lane and another nurse, Carrie Luciano, tried to block the way.

"He grabbed my left hand ... and twisted my arm," Lane said. "He kicked Carrie and she went flying in one direction and he went in the other direction."

The prosecution played a time-lapse surveillance video for Judge John Donohue, who is hearing the case without a jury. The video showed Luciano falling to the floor near the elevator but did not show what caused her fall.

In her opening statement, defense lawyer Celia Gordon said Kennedy was acting on instinct rather than intent when he kicked at Lane.

Kennedy's wife, Molly, came to court with him on Monday. The couple issued a statement in February that said, "Our simple desire to take our son outside for fresh air has been warped into a charge of child endangerment."

Kennedy is the 10th of 11 children of Robert and Ethel Kennedy. His father was assassinated in 1968. President John F. Kennedy, his uncle, was assassinated in 1963.