I've heard this before. I think better term than parasite is an addictive drug since we created these types of pet dogs and indulge on them. I feel strongly the trend of dog ownership overtaking people having children, while real, is more so a result of modern economic realities regarding cost of housing and raising a child.
Cost is definitely a factor, but I think the ease and convenience of a dog over the stress of children also plays a big role. Dogs are obedient and mature in less than 2 years.
