I guess you have bought the whole abduction storyline hook, line, and sinker then. There is no evidence other than these stories that what is being told is true. Not one iota of evidence that has been tested! NOVA did a program "kidnapped by UFOs" about 10 years ago. Their webpage is very telling when it comes to physical evidence:

http://www.pbs.org/wgbh/nova/aliens/wheresphysev.html

Some excerpts:

In interviews and in writing, and specifically in a letter sent October 17, 1995, we offered several abduction proponents the opportunity to have NOVA hire independent scientists to examine any physical evidence from a current case. We went so far as to offer to perform an MRI or other radiological tests (with the approval of a physician) in cases of alleged nasal implants. We were not taken up on our offer, and it was further suggested that the aliens are too smart to let such evidence fall into our hands.

I suggest you get a copy or, at least, read the transcript. I remember watching Budd Hopkins try and prompt a little kid into pointing the "grey" out of the lineup as the bad man. It was very sad to see somebody stoop to this kind of prompting. It was also very disgusting.

If you want to believe in the abduction phenomena, feel free to do so. However, do not come in here and suggest it is a real physical phenomena unless you have something to back it up. To date, all the evidence points towards a psychological phenomena. Abduction proponents are guilty of keeping these people from seeking help by feeding their fears and suggesting they are so special that science/modern medicine can not help them.