Parents' own birth order can become an issue when dynamics in the family they are raising replicate the family in which they were raised. Agati notes common examples, such as a firstborn parent getting into "raging battles" with a firstborn child. Both are used to getting the last word. Each has to be right. But the parent has to be the grown up and step out of that battle, he advises. When youngest children become parents, Agati cautions that because they "may not have had high expectations placed on them, they, in turn, may not see their kids for their abilities." But he also notes that since youngest children tend to be more social, the youngest parents can be helpful to their firstborn, who may have a harder time with social situations. These parents can help their eldest kids loosen up and not be so hard on themselves. Mum Susan Ritz says her own birth order didn't seem to affect her parenting until the youngest of her three children, Julie, was born. Julie was nine years younger than Ritz's oldest, Joshua, mirroring the age difference between Susan and her own older brother. I would see Joshua do to Julie what my brother did to me, she says of the taunting and teasing by a much older sibling.

I had to try not to always take Julie's side. Biases can surface no matter what your own birth position was, as Lori Silverstone points out. As a middleman myself, I can be harder on my older daughter. I recall my older sister hitting me," she says of her reactions to her daughters' tussles.