Sparkling guardians are very rare; there are currently only 4 in existence. Unlike normal Cybertronians; Sparkling Guardians are born with a Golden Spark. It is their duty to protect and help raise Sparklings.

Chances:

There is no more than a 10% chance of a guardian being born if neither parent is a guardian

There is a 60% chance of at least 1 guardian being born when at least one parent is a guardian

There is a 70% chance of at least 1 guardian being born when both parents are guardians.

Current Guardians And Side:

Beta - Autobots (Oldest)
Flowerdancer Prime - Autobots (Second Oldest)
Savage - Autobot (Third Oldest)
Bumblebee - Autobots (Youngest)
Skyfire - Autobot (Not Known That He Is One)