1996 — Gary Smalley, Making Love Last Forever, Thomas Nelson (1996), →ISBN, page 182:
On the positive side, middleborn children are good negotiators and adaptable; they often feel little need to "control."
2006 — Kevin Leman, Single Parenting That Works: Six Keys to Raising Happy, Healthy Children in a Single-Parent Home, Tyndale (2006), →ISBN, page 88:
Chances are very strong that the rebel in your family was a middleborn child.
2012 — Jonathan Caspi, Sibling Aggression: Assessment and Treatment, Springer Publishing Company (2012), →ISBN, page 37:
The middleborn child is the outsider in this form of sibling triangle and has less power in the family than the lastborn who is supported by the firstborn.
Noun: "the middle child to be born to a parent or family"
Middleborns and only children score about the same, but for different reasons.
2009 — Kevin Leman, The Birth Order Book: Why You Are The Way You Are, Revell (2009), →ISBN, unnumbered page:
Yes, I realize that you may be a middleborn who thinks your siblings got all the privileges or the breaks or the spoiling while you had to toe the mark.