Re: Can I breed my younger female to a second generation male?

Genetically, the daughter Cocker Spaniel, received half of her chromosomes 
from her mother and half from her father, as would any "son" of this same 
mother. If daughter and son have different fathers, half of their 
chromosomes would still be the identical since they share the same mother. 
Although not as bad genetically as mating son and daughter from a common 
father, this situation would not be ideal because any recessive genetic 
diseases could appear in the offspring of this mating. Since both daughter 
and son share identical chromosomes from the common mother, there is a 1/2 
X 1/2 or 1/4 probability that an offspring would receive identical 
chromosomes that originated in the common mother. 

Although I'm not familiar with AKC guidelines for breeding, I would think 
that this would not be a good idea and would "weaken" the bloodline.