If Both Parents Have Blood Tye O+ What Blood Types Can Their Children Have?

If both parents have blood type "O" ,  their children will have only the possibility of an "O" bloodtype. As far as the RH factor (the + or -), the children could be either one, so these parents' kids would be only O+ or O-.  

The other person who responded with the answer of "just about any blood type" is completely incorrect.

O is recessive and for both parents to be o type means that they are pure breeding for o, being both oo and oo, called homozygous recessive. These parents can ONLY have o type children= oo because neither parent has an A or B to pass on.

Both of my parents are O+, as am I but my younger sister is B+

I know people who were both o+ and ended up with an a+ child