Single mothers saying they're the father.

Why do single mothers say they do both roles ... ?

No you are a great single mother trying your hardest. You're not the father so stop telling people that you are your child's mother and father.

Go ahead and prove me wrong because maybe I don't understand.

Yes I'm a single mother and my sons father left him out of no where and hasn't even called him. He told me he wants nothing to do with us .