You are right to ask, and in a perfect world we want to have perfect females too. But we will give a little for a female as she may have so much to offer even if she is not perfect. She may produce one or two in her litter that are very nice examples of the breed if breed to a very nice male. But if you breed this bitch to a terrible male you will not improve anything. The boys are used more than a bitch will ever be breed( I hope) so they need to be good or even great . I hope I have explained this for you. Good breeders don't keep mediocre males and none keep pets in their breeding stock.
Debbie Ray
www.sumtoiyorkies.com 
These are my boys and I am very proud of them. They are both AKC Champions and Tailor is an Int. and Canadian Champion also