There is a large contingency of people who believe in aliens and extra terrestrials. There are endless stories of abduction by UFO aliens, unbelievably performing spacecraft and ancient myths. One of the most intriguing and plausible explanations of why alien species are here or come to visit with us mostly harmless humans is to inter bread with us and repair their genetic flaws, which over hundreds of thousands of years had caused damage to their DNA. Some scientists have helped propel these myths but providing interesting information we have learned thru the space program about issues with radiation in space. For long-term space travel we must find solutions to protect us from the radiation, which might also damage our DNA. Thus conspiracy theorists and UFO-logists have hung onto this theory of why they believe the aliens are abducting people and as per the stories of the abducted seem to be quite interested in the human reproductive bio-systems.
Now then, let us discuss the flaws in these theories. First a civilization which may have been transplanted to this planet thru necessity or exploration outpost or colony would already have complete control of their DNA and bio-systems and thus have no need to introduce the human DNA into their lines as it would be somewhat weaker and less evolved. An advanced species which had control of their DNA would not have innate needs for procreation or need sex and thus would have figured out a way to clone without DNA replication loss issues. Additionally a species, which was far advanced would not be worried about DNA damage and would simply fix those issues themselves without having to splice genes from human beings. They would be able to genetically modify their DNA to over come any loses or replication issues from long-term space flight due to radiation or any issues with in-breading from their small population of alien space colony travelers.
Indeed whether you believe in aliens, UFOs or extra terrestrials is irrelevant to the question of if such a story is plausible, as it does not stand to reason. The legends, ancient writings and theories do not seem to hold water. As science learns more about DNA and as our own species becomes transhuman we will be able to better debate these alien urban legends and their flaws.
"Lance Winslow" - If you have innovative thoughts and unique perspectives, come think with Lance; www.WorldThinkTank.net/wttbbs