The egg....becuase?
lets put it in a situation...
lets we we decide to clone a chicken

if we clone it..what do we do to get tha clone?....an Egg..cause we need a egg to start the life..so we have a egg to start life......and we use the egg to start the life....becuase theres no other way...unless your god...anyway....
why the egg?...because its the start of life.XD
I just think...things needs to begin to live....not just appear...but...go through the cycle of life?
buts that just me.............