When we had one child, oh, my, what wonderful parents we were.

Our little Prince got onto a predictable sleep schedule at three months, ate a wide variety of foods by toddlerhood and said please and thank you at preschool.

When he started "acting out" at age 5, we bought a book on discipline, followed its directions, and, wow -- it worked! Parenting was so easy! We were naturals!

Then we had our little girl...
Our daughter, we all agree, falls under the category of "spirited."

She tantrums when she doesn't get her way, refuses to eat anything distantly related to a vegetable (even green Goldfish crackers are excluded) and has the handiest knack for getting her way through sheer force and volume (no idea where she gets that from).

Is she just programmed this way? Or are we different parents with her than we are with our Perfectly Behaved Son?

Researchers from top universities, including Duke and Johns Hopkins, say parents are tougher on their first-borns. And that's a good thing. The study focused on adolescents, with the goal of figuring out which teens make risky choices and which ones don't. The researchers presented "a mathematical model that supports such unequal treatment of children because more severe discipline of older children deters younger siblings from engaging in the activities for which they know their older siblings were penalized."

Bottom line: Be tough on your first born. His younger siblings will learn from it.

Apparently first-borns are less likely to engage in risky behavior because they know Mom and Dad will come down hard on them if they do. Right there with you on this. But, the researchers warn, as kids start to go off to college, there's less incentive to "set a good example" for the little ones, so Mom and Dad tone it down. As a result, the youngest kid gets away with more and is more likely to engage in risky behavior.

I would add that even when both kids are small and right there in your house, Mommy is very exhausted from saying no to that first kid, and is less capable of being the smart and stern disciplinarian she knows she should be for the second kid.

With the first child, it's easy. You've had a little time to study and then you also get to take the occasional nap. Also, I have to confess that part of me feels like my little one, even at age 4, is still my tiny baby, and I admit it, I baby her.

That said, this research indicates that our goal should be to maintain that wonderfully strict vibe we all had going with our first child (remember?), with all our children, particularly when the kids approach teen years.

I can see how being equally strict with each child is ideal, but is it possible?

Who do you discipline more: Your oldest or your youngest? And if you are able to be as strict with your youngest as you were with your oldest, please, please share how you do it.

Sabrina Weill is editor of PrincessLovesPink.com