Can a couple who are both o positive have 1o negative baby and 1 o positive baby

i am o positive my ex husband is also o positive we have 2 children my little boy is o positive but my little girl is o negative is that possible please let me know cause my ex is not claming her because his wife says theres know way shes his because of her blood type and I never cheated on him but he has me

His new wife is dead wrong.

It's true that two O blood type parents can only produce a child with the O blood type as in your case. However, the Rh (+/-) factor is inherited separately from the ABO blood types.

2 parents with Rh Positive blood types can have a child with Rh negative blood type.

Details on blood types:

http://www.canadiancrc.com/paternity_determination_blood_type.aspx