Aliens are all bastards for simple reason.
they do not believe in marriage.

Aliens are bastard because they constantly made McCoy yelled "Dammit Jim! I'm a doctor not a/an (insert random word here)."

Why are aliens bastards? I can sum that up in just one word.

Crysalids. Fucking crysalids.

That said, they're also stupid bastards. Instead of bringing their full force to bear on earth from the very beginning, they instead sent in their forces piecemeal, starting with only weak, easily captured scouts and only sending in progressively stronger forces when the humans have had time to capture and reverse engineer their tech. By the time they send in the battleships, the humans are bringing them down with plasma-cannon equipped UFOs (well, not really, since they are in fact identified, but you get what I mean) of their own and soldiers armed with flying power armour, plasma weapons and psi powers of their own and supported by a plasma cannon equipped mini hover tank.

If they'd just broken out the battleships, crysalids and ethereals from the very begining, Earth would be powerless to defend against them and would be theirs within a month. Overwhelming force, guys, it's not a difficult concept. We earthlings figured it out almost as soon as war became a thing.

But yeah, fuck crysalids. Those things can eat a thousand dicks.

By "aliens", you mean the xenomorphs from the Alien franchise? And by "bastards", you mean "someone not born to a married couple"? If I can remember the xenomorph birth sequences correctly, I think that from here on, the reasoning is pretty straightforward.

I'm in .

Aliens are all bastards because of this ?

Aliens are bastards, because they took our jobs.

Also, there's this thing with the crop circles -- they have the technology to travel through the vastness of space and they use it to pull childish pranks on farmers? Bastards.

Why not? We use ours to draw giant penises on the surface of Mars.

Because they have no balls.

I'm in, thanks.

Because their father didn´t want to give them his surname as they were cloned :P

they're bastards because we made them bastards http://tvtropes.org/pmwiki/pmwiki.php/Main/AliensAreBastards

i'm in, thanks

Oh yeah? Well, they started it!

Count me in for Triock, please.
Aliens are bastards, because they are ugly parasites actually look nothing like Natasha Henstridge's Species.
Thanks Bigs for the nice collection.

I hope GOG doesn't mind I put the pic of an alien, not a sexy female human.
http://upload.wikimedia.org/wikipedia/en/e/e7/Speciesver3.jpg

Because it's the second time they shot up my ride and drank all my beer.

Nice, southern France? :P