When people ask me if I have kids, my standard answer is, "I have a dog." My husband and I are the first to admit that we tend to treat our pup like a "real" child. He eats organic food. Our apartment is littered with ripped plush toys. We talk to him in stupid high-pitched voices. He spends almost all of his time with us, including sleeping and vacations. When he's not with us he's at a daycare center down the street — and I spend much of that time worrying about whether he's OK. It's probably not a full-blown separation anxiety disorder, but when we're separate, I'm anxious.

On an intellectual level I understand that having a dog is not the same as having a human child. Still, what I feel for him has got to be something like maternal attachment. And a new brain-imaging study backs me up on this.

Researchers from the Massachusetts General Hospital scanned the brains of 14 women while they looked passively at photos of their young children, photos of their dogs, and photos of unfamiliar children and dogs.

As it turned out, many areas of the brain involved in emotion and reward processing — such as the amygdala, the medial orbitofrontal cortex, and dorsal putamen — were activated when mothers viewed their own children or dogs, but not when they viewed unfamiliar photos.

Of course, we don't really need a fancy (and expensive) neuroimaging experiment to demonstrate how much dogs mean to their people. Two-thirds of American households have pets, and we spend a whopping $58 billion a year to take care of them. Upon losing a pet many people experience intense grief, similar to losing a close friend or family member. And dogs, too, show attachment behaviors toward their caretakers just as human children do.

Still, the imaging results add some interesting nuance to the dog-human relationship. For example, a brain region known as the fusiform gyrus was activated more when mothers looked at their dogs then when they looked at their kids. This might be because the area is involved in face processing. "Given the primacy of language for human-human communication," the authors write, "facial cues may be a more central communication device for dog-human interaction."

Conversely, two areas in the midbrain — the substantia nigra and ventral tegmental area — were active when mothers looked at their children but not when they looked at their pups. These brain areas are lousy with dopamine, oxytocin, and vasopressin, chemicals involved in reward and affiliation. This could mean that these areas are crucial for forming pair bonds within our own species, but not so relevant for the bonds we form with pets.

These results come with the usual caveats for brain imaging studies. It was a small sample of only women, and the brain snapshots were taken at just one point in time. Nevertheless, I think studies like these offer important counter-points to what I see as a growing trend of poking fun at pet-human bonds (even by pet owners themselves).

No, I don't personally endorse doggie birthday parties, 22-karat gold leafed food bowls, or even pet chemotherapy. But neither do I begrudge those who do. Dogs may not be children, but they're still our babies.