If the mother is b negative and father is o negative what will happen to the pregnancy

If mother blood group is b negative and father blood group is o-

What's your question? The kid could come out with b or o blood. If you're trying to determine paternity though, you'll need a DNA test as blood tests are not accurate in determining paternity

Are you referring to the RH factor?

As long as a partners both have - (negative) or both have + (positive) there are no additional risks to the fetus.

If the parents have + and -, the mother is usually placed on medication during the pregnancy.

Can a B negative mother and a O positive father have b negative child

If the father is O negative and the mother is B negative then the child would be either O negative or B negative only.

Under the common ABO blood typing process, a person's blood type could be A, B, AB or O. It is very important for people to know their own blood type, as well as that of their spouse and children. Important decisions concerning emergency blood transfusions may have to made quickly, so having this information on hand for medical professionals can shave precious minutes off the initial triage process following a trauma. A person's blood type is determined largely by genetics, and it does not change through his or her lifetime. A simple blood typing test can be performed literally anywhere by anyone through the use of specially-treated testing cards.

I received this information from my blood specialist Doctor.

One of the main factors that determines blood type is family genetics. A child receives separate sources of genetic code, called alleles, from each parent at the time of conception. One of the alleles located on chromosome 9 contains the precise type of the donor parent, and is classified as A, B, AB or O. An additional factor is called the Rhesus factor, which could be positive or negative. The actual blood type of a child is determined by the dominant type between the two parents. A and B are both dominant over O, which means a child that receives an A from the father and an O from the mother will have a type A blood.