[MyFairLacy]

There is no such thing as a teacup anything. A yorkie is a toy breed that should be 7lbs or under.

I've seen from reputable breeders on here that a female should be at least 5lbs to be bred. But size of the female and male is not the only thing you have to consider. You need to know the family history of both dogs. You need to know the size of the dogs in the pedigree. If you have a larger yorkie back a generation or two, then you could get a throwback puppy...one that grows much larger than the parents. You really want to use dogs that come from lines of fairly consistently sized dogs that meet the standard. You also need to look at the females in the pedigrees...are the free whelpers or has there been a history of c-sections?

There is much more involved than just looking at the size of the female and male you want to breed