If Dad is blood type 0- and Mom is 0+, what is/could be the baby?

Could be anything, but it would be something that is in either Dad or Mom's genetic background. DNA testing has proven that the simplistic stuff you learn in high school is just that. Simplistic. Not accurate.

My parents are both O positive. Of their 6 biological kids, 3 are O positive, 2 are O negative and one is A positive. No question on paternity. We know my paternal grandmother was O negative. Don't know where the A pops in, but the percentage is quite high in my great-grandparents native countries.

toddler could have something. opposite to what a lost of posters have suggested, somebody with O blood can also have a baby with A, B or AB. O is in basic terms dominant. the two my mothers and dads have been O effective and that i'm O damaging as is my brother. I also have a sibling who's a superb and a couple of who're O effective. No telling what you may get, yet I assure that there is no question approximately paternity!

the baby could have a completely different bloodtype all together, it could have the maternal grandmother's blood type or the paternal grandfather's. It's too hard to determine which one will have the mom or the dad's blood type.

my oldest has her dad's- A+

my second has her grandmother's- O-

my third has mine- O+

and my fourth has- A-

O either + or - for all children