The Times reported that there were no numbers to indicate how widespread the practice is in the US, but there's reason to believe it's common. One 2003 study of 401 students at five medical schools in Pennsylvania found that 90% had performed an unconscious vaginal exam on a patient. The researchers didn't look into how many obtained explicit consent beforehand. But they did find that students who'd completed a gynaecology clerkship thought consent was less important than those who hadn't.