This was an unexpected result but Hill and her co-researchers believe the fact that the tests were carried out in an unromantic campus health centre also played a part. Over the past year they have run the tests again in a softer setting complete with romantic background music.

I wouldn’t call it unexpected at all.  From what is becoming manifestly clear, oxytocin is a chemical produced by the brain in order to promote long-term bonding.  In an unromantic setting, it would clearly not be in a female’s interest to establish such bonding as a result of a sexual encounter.  Of course, romance doesn’t play such a huge part in the male sexual response, thus it is no surprise that a man’s oxytocin levels can rise even in such an artificial lab style setting.