About the "Tea Cup" Phenomenon
This article pertains to the Maltese.  However, it can be
associated with any and all of the toy breeds.  Some Yorkies
are smaller than others, but the breeds preferred standard
weight recommended by AKC should be between 4 and 7
pounds.  
Actually, “there is no such thing as a teacup Maltese ”
quote by Daryl Martin a Maltese breeder in Highland
Park, Illinois. “The whole teacup phenomenon is a
horrible thing because the breed is already small, but
the tiny ones tend to have many health problems, from
water in the brain to liver shunts (abnormal veins that
result in failure of the liver to metabolize toxins and
brain inflammation)”  

“You will pay a lot of veterinarian bills,” says Ingela
Gram, A breeder and AKC licensed judge in West
Redding, Connecticut, who adds that the so called
“teacup Maltese” often have the Chihuaha-esque,
apple-domed skull and an open fontanel, a skull shape
that isn’t conformationally correct for the Maltese.
“They usually aren’t healthy, they have many
problems” Gram says. “When you get a dog down to
two lbs, nothing develops like it should. The heart is
too small, the liver is too small.
Do you want to end up
going to the vet all the time?
People forget about that,”
Gram adds.  

“You wouldn’t see a so-called “teacup Maltese” in the
show ring, because this super-small-sized Maltese
weighing in below the preferred minimum of 4 lbs, is
often associated with incorrect conformation, such as a
skull that is too apple-domed.” (Quote taken from
Ingela Gram Maltese breeder and AKC licensed
judge)  

A Maltese may occasionally be born small, but a tiny
size is no advantage, agrees Vicki Fierheller, a Maltese
breeder in Toronto, Ontario, Canada. Despite the
health and other issues, some unethical breeders try to
profit from the tiny dogs cuteness and rarity. Some
unscrupulous breeders purposely breed for the
“teacup” Maltese because they can sell them for much
more money, but so often the wee ones have more
health problems.
There is no doubt these puppies are
adorable, but I would be very cautious about getting
one!

Article taken from Popular Dog Magazine Volume 29