However his actual biological father lives a few doorsteps away.

The man is revealed to be his actual father from the parallel universe, "Walternate".

The mother, through a cellologist, had registered the actual father.

He still had enough problems over how he felt about his actual father.

The name and identity of Corc's actual father is something of a mystery, however.

The actual biological father of a newborn can also be confirmed (or ruled out).

This man may or may not be her actual father; Roberta is never quite sure.

He'd been helping to take care of them all since their actual father died in 1986.

Further to the point, Borden-2 would not be the actual father to the children.

He encourages her to take a test, but she refuses, stating that she'll lose everything if Chuck is the actual father.