Human Genetics Problem Set
Problem 19: Who is NOT the father of my grandson?
The following is an edited version of an email exchange that occurred in response to the human genetics tutorial at the Biology Project:
First Message from a concerned grandmother:
Answer to First Message by Professor Hallick:
I am wondering how to find out blood type of my grandson...my daughter is
A+..father is in question...she is stressed to the max on the father of
this baby boy.
What is the most common blood type and the most common donor and common
Blood type analysis can occasionally rule out a potential father (i.e. if the
mother is type A and the child is type O, the father could not be type AB, but
could be type A, B, or O), but is not a method that can be used to establish
If the paternity of your grandson needs to be established for legal reasons, such
as establishing responsibility for child support, a DNA test would be the
accepted method. There are
commercial laboratories that will do the test for a fee (several hundred
dollars). Blood samples would be required from the mother, child, and any
Second Message from grandmother:
Thanks so much for your prompt reply. Here is the scenario....paternity
isn't going to be established...it is going to lay...for lack of a better
expression. My daughter is type A, my grandson is type B+, we do not know
the types of the two gentlemen in question...my question is what are the
types that the fathers would have to be in order for him to be a B+?
What is the correct answer to the grandmother's question, "What are the
types that the fathers would have to be in order for him (grandson) to be a B+?"
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Revised: November 5, 1998
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