Ever think about buying a goldendoodle or a chiweenie? So-called designer dog breeds are cute, with trendy names. But before you go for the latest Frankenbreed, here’s a couple of things to consider.

First, these crosses are mixes with known ancestry, not purebreds, so the pup’s adult size and characteristics are less predictable. Second, some genetic combinations may create a perfect storm of illness. For example, mixing a pug and a Boston terrier gives you an adorable bug but may also multiply the respiratory problems common in smushed-faced dogs. Likewise, crossing a golden retriever and a standard poodle may magnify the hip and eye problems found in both.

So if you’re in the market for a designer dog, make sure you deal with a reputable breeder. Or try checking animal shelters and breed rescues for a healthy orphan looking for a good home.