. >>> judd unplugged. she's got a new role as one tough mother. tonight ashley judd talks about training to play ex-can cia agent, why she ditched hollywood, and why she came back. this is "nightline," march 19, 2012. >>> good evening. tonight we begin with one of mother nature's most enduring puzzles, female sexuality. it's been more than a decade since viagra became the go-to for male sexual dysfunction. now a team of scientists has an intriguing hypothesis, for the ladies. when it comes to achieving climax, we may have been fixating on the wrong body part. >> just make yourself comfortable. relax. >> reporter: you'll never believe what these women are doing. it's the subject of documentary and scientific studies. >> are you nervous? >> a little nervous. yeah. cameras. >> the performance in question, requires kate to master bait to orgasm inside a less than romantic mri machine? >> are you ready? >> i'm ready. >> barry and his team of researchers here at rutgers university are monitoring every detail of her climax. >> her pupils are dilating. >>