I hope that the following background information helps to answer your question. Blood type is an example of a trait determined by a single gene. Each of us has two copies of the gene for blood type. We inherit one copy of the gene from our mother, and the other copy from our father. There are three different forms (called alleles) of the gene for blood type called A, B, and O. Blood type is determined by the combination of alleles inherited from our parents.
A person’s blood type is called their phenotype, and the different genetic combination of the forms of the gene is called a genotype. An example of a genotype would be OB. In this example, the person has two forms of the gene, O and B. This person’s blood type or phenotype would be type B blood. As the previous poster mentioned, O is a recessive form of the gene. In order for an individual to have type O blood, they would have inherited one “O” allele from the mother and one from the father and have the genotype OO. A and B forms of the gene are codominant and can both be expressed together.
Type O blood is recessive so, to my limited understanding, two type O parents each have O-O genotype and will almost always have a type O child, barring a mutation of course.
So, assuming no initial error in blood typing was made with any of the parties, with a mutation it is possible, but the mutation is not likely.
There are genetic tests available for maternity/paternity that are more in depth than blood typing.
Copyright 1994-2018MedHelp.All rights reserved. MedHelp is a division of Vitals Consumer Services, LLC.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.