Are Children Oxytocin Dispensers?

Shankar Vedantam Hypothesizes:

"Children regularly give parents the kind of highs that only narcotics can rival. The unpredictability of those moments of bliss is an important factor in their addictiveness. If you give animals a predictable reward—say, a shot of sugar every time they press a lever—you can get them to press that lever quite regularly. But if you want irrational and addictive behavior, you make the reward unpredictable. Pressing the lever produces sugar, but only once every 10 tries. Sometimes, the animal might have to go 20 or 30 tries without a reward. Sometimes it gets a big jolt of sugar three tries in a row. If you train an animal to work for an unexpected reward, you can get it to work harder and longer than if you train it to work for a predictable reward.
We've all seen those sad people sitting at slot machines in a casino, methodically feeding coin after coin into the slots. If you made their reward predictable—after precisely every 20 attempts, they would always get a prize—you would lower the addictive power of slots. It's the unpredictability that drives them. Or, to put it another way, it's the hope for reward, not the reward itself, that drives them.
I suspect oxytocin works the same way. The unexpected, kind, and loving things that children do produce chemical surges in their parents' brains like the rush of the pipe or the needle. Like addicts, parents will sacrifice anything for the glimpses of heaven that their offspring periodically provide.
I don't know if there is empirical evidence to back me up, but it's conceivable that the neurological mechanisms of addiction—in all their irrational and self-defeating pathologies—are based on underlying mechanisms in the hidden brain that are designed by natural selection to make us seek out—and enjoy—parenthood."