Welcome to Yorkie Talk. The genetics that determine size go back farther than the parents. That is why good breeders will study their lines when making a match to breed.
My boys are full brothers, different litters, and they are significantly larger than their littermates. Even good breeding can throw curve balls.
The weight pairing that you are asking about probably will produce standard size Yorkies, the standard being 7 pounds or under.
Female Yorkies do not tend to be larger than males in general, but breeders usually pair smaller males with larger females. If I understand correctly, part of the reasoning is that the smaller male will help produce smaller pups, while the larger female can carry a pregnancy easier -- and maybe produce more pups in a single litter.
__________________ Kristin, Max and Teddy  |