Alien visitations and abductions, do they really happen? I don't doubt that in the vast cosmos of our multiverse there are intelligant life forms out there.
(just my opinion) To believe otherwise from any stand point, scientific or religious seems ludicrous to me. Do these non terra firma, interstellar beings come to earth for scientific experimentations? Probably not.
If Aliens decided to zing by the earth and check out the primitive carbon based entities on this planet, they could be doing so for the following reasons. (these are the specultaions of some who work night shift and listen to strange talk radio.)
1) Giving earthlings (through intermediaries, like the government) technologies in exchange for handing the planet over to them on a future date. (possible technologies aquired, velcro, CD/DVD's, nuclear fission etc. etc.)
2) The alien species through excessive cloning could be coming to earth to take our primitive gene pool after destroying their own. Over cloning could have made them evolutionary dead ends, and they need a little terran pick me up juice, to revitalize their species for survival.
3) You ever see a boy no matter his age or current frame of mind be able to resist walking past an ant hill with out kicking it? There's just something about watching the ants scurry around in a mad dash tizzifing themselves to protect the collective hive. Perhaps there is that crude little boy gene in alien life forms and the earth is an irresistible giant ant hill, where they can come by and give us a kick to stir things up. (whenever UFO's have been reported what do we do? Run around in a tizzy)
If an alien species is advanced enough to create a space traveling vehicle that could reach our little corner of the universe during their life times. Do you honestly think they would need to shove metal objects in our anus (Rectum, ass meats, tush, glutious maximus.......you get the picture), cranium or other odd experiments that seem to happen to certain people.
I also don't believe that an alien species needs to steal the sexual organs from cattle in the name of their science. If they could get here to begin with, I think they would be beyond such crude scientific experiments.
Perhaps I am wrong, these assumptions could be based on the common belief that aliens are bipedal, gray's, with black wrap around eyes. (you ever notice that after Spielbergs movie 'Close Encounters of the Third Kind' was released that there was an explosion of Grey's abducting humans being reported?)
Who are we as humans to suggest that intelligent, alien space beings who travel the galaxies even look remotely like us. What if they look something like giant spiders, or at least like spiders as we understand them. Or if they are Cilicone based then why not look like Gastropods. (Slugs and snails)
If the United States can create a super spyplane like the SR71 Blackhawk which has flown a few hundred 'offically' claimed missions, why then does the B2 Bomber seem to fall out of the sky so often? Especially if it is supposed to be a far superior plane. Oh and why cant we make a space shuttle that is more aerodynamic.
The tough part about space travel is punching past our earths gravitational pull. Once we are free of that bad daddy of a physics lesson it seems (from what I have seen on NASA tv) that space propulsion would be a breeze, a walk in the park, or a piece of cake.