Federal authorities are investigating Pennsylvania’s Shippensburg University for having the morning-after pill Plan B in its vending machine.

The university installed the vending machine two years ago when 85 per cent of the students voted in favour of the idea.

Some are concerned that the current arrangement would make Plan B, which is typically sold behind the counter, available to women under 17 without a prescription, violating federal law.

However, university spokesperson Peter Gigliotti noted that the machine was in a building only accessible to students.

“You cannot be a 13-year-old and walk in and get it,” he said.