different blood types of father and son

I am A positive blood type, my wife is A positive, we have a son who is O positive.  I have always had doubts about paternity. Can this difference of blood types show anything?

[eureka254]

It is not unusual for blood type A parents to have blood type O children, since O is a recessive trait.  Your son having blood type O does NOT indicate non-paternity. In other words, you and your wife, though both blood type A, a dominant trait, may both carry a gene for O blood type.  You can find a good explanation of genetic inheritance patterns at the following site:

http://anthro.palomar.edu/blood/ABO_system.htm

Hope that helps.