Don't freak out yey. Mutations happen. I happen to have one of my own. Your parrents may also have used a sperm donor.

I have the same problem! My dad is 0+ my mom is o- and I'm a+. Wtf?

It actually is genetically possible... you can be o -b just like u can be a- b ... its sorta like the o is dominant, but there is a chance of b.

or a sperm doner!!

Actually it is possible. There is a special mutation called the Bombay phenotype that makes people with A, B, or AB phenotypes test as O because the mutation disables the antibodies on the cells normally used for blood typing. It is a rare condition though, and not dangerous, but it is possible.

I'm a different blood type then my parents I hope I'm not adopted ;(

yes it is O's can give to every blood type

During my first year genetics module, we were told that we couldn't test our own blood groups because of a story like this. Sorry you have to find out this way. Just one point though - Bombay phenotype is not being A/O or any other combination. Essentially you are none of them as in the Bombay phenotype, one of the essential molecules for the ABO system is missing. While you would show as O on a blood typing test, if you were given blood from anybody who does not have the Bombay phenotype, you would suffer a potentially fatal reaction. You can however give blood to anybody else. It is possible that one of them is wrong though? Do you know their blood group for certain?

You should go with mutant

Sux, you were either adopted or your mom did it with another man. I can't figure out my blood type, cuz my doctor doesn't have it, and I don't feel like going to the hospital. My mom is A, my dad is B. I can be A, B, AB, or O. I won't be able to tell if I was or adopted or any of the shit that happened to you. :P