Barack Obama has promised the future First Daughters a dog, and his eldest, 10-year-old Malia, has zeroed in on a so-called hypoallergenic breed to accommodate her allergies. Her top pick is a goldendoodle, a cross between a golden retriever and a poodle, though the future prez has hinted about adopting a rescue dog, noting that "a lot of shelter dogs are mutts like me."

We asked Bernadine Cruz, a spokeswoman for the American Veterinary Medical Association, to explain the hypoallergenic concept. Cruz is a veterinarian in Laguna Hills, Calif., and in 2006 was also a paid spokeswoman for Allerca, a company that claimed to have bred a hypoallergenic cat. For an update on Allerca and its research, see this story in The Scientist.

This is an edited transcript.

Why are some people allergic to dogs?

For many people, being allergic to dogs is a matter of having a sensitivity to a protein in their saliva which also exudes through their skin.

Would a hypoallergenic dog be a good option for people who are otherwise allergic to pooches?

There is no such thing as a hypoallergenic cat or dog. One cat has been bred that's considered hypoallergenic: A company called Allerca in San Diego found a line of cats considered hypoallergenic because of a naturally occurring divergence (mutation) of the protein Fel d 1. The protein is (normally) found in cat saliva, urine and exudes from their skin. I've found people who are extremely allergic to cats who are able to play with them and not have the sneezing. But in dogs, a mutation in any similar protein has not been found.

What types of dogs might be better for allergy suffers?

Every person will have his or her own degree of reactivity to certain dogs — their saliva and proteins in their bodies. Those dogs that are more universally less allergenic come from more specific breeds such as Poodles, Kerry Blue Terriers, Schnauzers, Bichons and Lhasa Apsos. [They] don’t shed a lot or they go to the groomer frequently and by getting their hair washed and trimmed, get the allergens off their skin. When those dogs mate purposely or accidentally with breeds outside of those breeds, their offspring may be less allergenic.

But some people can have allergies to a Poodle and then be playing with a German Shepherd and have no problem.

What about the Peruvian Hairless Dog, which that country has offered to the Obamas? Is it better for allergy sufferers?

They're not going to be shedding a lot, but (allergenic) proteins will exude through their skin so that’s not always going to be the answer.

Are purebred dogs healthier than other dogs?

There's no difference.

Are purebreds available at shelters, or only through breeders?

Many times you will find them in shelters. Going to shelters or breed rescues is a great way for the Obamas or anyone to get a pet.