I spotted this joke in one of the famous jokes page called Mathare University of Insane creativity.. I think it is worth enough to share with you.

Mother: Son I'm sorry I slept
with someone that is not your
dad 23 years ago. And that
person is your real father.
Son: Mum, what rubbish! How am
I to deal with this?! You should
be hanged.
Mother: I am sorry he was my
first love and I could not marry
him... because we are of
different religion. He is on the
phone at the moment and wants
to speak with his son for the first
time ever.
Son: No I am speaking to no one.
Bob is the only father i
know and so will that be.
Mother: Please don't be so upset.
Just talk to him.
Son: Ok, I will give him a piece of
my mind!
Phone: Morning Son, I am Bill Gates . I am your real father.

Son: Dad! Dad!! Dad!!! Thank God!
Ohhhhhhhhhhhh Thank God!!!!!!
Love u so much Dad!!!!! I’ve
been looking for you for so long