If you find out that you have a sister or a brother somewhere, what would you do? Would you contact her / him or just forget about it?

Would you keep it a secret from your children if you have had a child before your current family?

What if you were a child, born to unmarried mother and never met your father, would you be angry or bitter? How would you react if you knew you had siblings?

These are questions that goes round and round in my head...