I have O negative.

My blood type is called the "universal donor" because every person on earth can receive my blood with no problems.

However, the only type of blood I can receive is O negative.

Kind of makes it the "martyr" blood type, doesn't it?

I can't donate blood. I have tried a few times, and I always end up passing out and scaring the living daylights out of the staff. The same thing happens if I have to get blood drawn for a test, or even if I get some shots. It's not a because the process upsets or disturbs me, I'm actually not bothered at all by needles, blood, etc.

The best any doctor has been able to figure out, it has something to do with the fact that I have very low blood pressure, and hypoglycemia.

RH factor is a problem that arises when a woman with negative blood is pregnant with a baby with positive blood. I had this when I was pregnant, and had to get shots before my son was born. I don't know remember the details now, but I think it has something to do with the potential for the mixing of the two blood types at birth. Could be dangerous for the negative typed mother, although not for the positive typed baby, I would imagine.