I want to know how do you know a baby is yours by blood type like if your mines was o negative and the female is a positive does it make a o positive baby

If : If your blood is o negative and the mother’s blood is a positive then yes, the baby can be o positive. The baby could be either o positive or o negative. However, the way to determine paternity is through a paternity test.

Yes. : Yes. O positive is a possibility.

See below: Blood type is not the usual mechanism for determining paternity. Possible blood types for the baby with those blood types you have mentioned are a and o. The rhesus antibody type could also be + or -. Hope this helps.