http://www.theregister.co.uk/2007/03/09/no_cropcircles_gm_crops/

See also http://www.weeklyworldinquisitor.com/feature_images/31.jpg

"The long-terms effects of these 'frankenstein crops' are just so
uncertain"
    Source http://tinyurl.com/yr6b83

[Quoting from El Reg ...]

' Aliens shun GM crops '

The reason why visiting aliens tend to abduct American citizens but
only trample on corn fields in Europe has been blamed on genetically
modified crops.

It seems the grey lizards are worried about carrying contaminated
genetic material back to their own worlds. Aliens are avoiding
creating crop circles in fields containing GM crops. A five year study
of crop circles found none appeared in fields containing GM crops.

The research work was carried out by Buck Uranus - and it's got to be
true with a name like that, right? Mr Uranus is funded by the William
H Carpenter Foundation which, like Mr Uranus, has managed to evade
Google.

Luckily for seekers of the truth Mr Uranus has not only carried out
detailed research into the crop circles but also talks to the aliens.

Uranus explained: "In my spare time I channel messages from alien
beings...these guys have serious reservations about what we're doing
down here. One even told me he's even thinking of using another planet
for his artwork." ...