Understand, the story isn't that aliens are impregnating earth girls.
The story is that there are some silly earth girls who are believing it.
Oh and here's another one. I think part of this conspiracy theory often says these nasty aliens impregnating earth girls might be "Nephalim" from the planet "Nibiru".
Did you read a couple days ago how the California Institute of Technology thinks there might be a ninth planet? Well these new age whackos think that might be "Nibiru".