All humans have blood, but not all blood is the same! We each have our own blood type, which depends on DNA passed down from  our parents. But what does it actually mean to be Type O-positive or Type AB-negative? Why is it sometimes really important to know your blood type?  We asked Dr. Emily Downing to help us find the answer. 

Got a question that’s so hard it makes your blood boil? Send it to us at, and we are positive we’ll find an answer.