There's something new to worry about these days: the disappearance of the middle child.

One of the side effects of shrinking family size is that middle children are disappearing. With more and more people having only one or two children, society is losing one of its great assets.

When Jesus said "blessed are the peacemakers," he may have been referring to middle children. Born between the older and the younger children, the mini-adult oldest and the baby-of-the-family youngest, middle children grow up negotiating a complicated family dynamic.

Middle kids are stereotyped as being resentful of their lack of status and power. They have a birth order chip on their shoulder about the glory hogs above them and the spoiled babies below. Think Jan Brady from "The Brady Bunch." That has not been my experience, however, and it's not what researchers are finding.

Indeed, middle children, one expert said, are "social beings and great team players." According to Katrin Schumann, co-author of "The Secret Power of Middle Children," a majority of our presidents have been middle kids. She identifies other positive traits of the middle child as independence, cooperation, heightened empathy and principle-driven rather than ambition-driven.

It sounds like society could use a few more middles these days. Alas, the demographics are moving in the opposite direction. According to data from Gallup, in the 1970s three children was the ideal U.S. family size and only 20 percent of families had two children. In 2014, the ideal has become two, with 60 percent of families having one or two children. (Only 20 percent have three and 10 percent have four or more.)

I grew up in a family of seven, which I considered "average." I knew several families with more than seven, and being a competitive oldest child, I thought my parents weren't trying hard enough.

Being seven, it fell to one of my sisters to be exactly middle. Her lot in life was to be too old for the youngest quadrant and too young for the oldest. She was the one who stayed home to babysit when the "big kids" got to go out. At the same time, the grandparents often doted on the younger or older, not necessarily the unfortunate middle.

Yet being put in a situation where she had to maneuver between the big kids and the babies, she became a peacemaker, a leader, a negotiator. Her empathetic skills are darn near legendary, making her an effective caregiver.

According to Schumann, middles "can see all sides of a question and are empathetic and judge reactions well. They are more willing to compromise," and "since they often have to wait around as kids, they're more patient." On top of all that, they score high on marital happiness surveys and tend to stick with monogamous relationships when their other sibs are throwing in the towel.

All of which sounds like traits currently in short supply. We are worried about global warming, trade wars, refugee crises and race relations. Maybe what we need to be worried about is the lack of middle children to help us find solutions to all these challenges. And the shortage is not just ours. Europe, Russia and China all have a middle child shortage.

The list of middle children who made it big is significant: Abraham Lincoln, Susan B. Anthony, Martin Luther King Jr., Anwar Sadat, Lech Walesa. I'm not sure how many saints were middles, but that is research just begging for a doctoral student.

So America, the challenge is clear: If we want to make our country great again, we've got to grow the middle.