In fact anyone who is the first-born child of a family knows that it isn’t an easy lot. The parents have never had a child before and they use the first-born to learn their parenting skills. With later children they are more confident.
In some cultures (the Biblical way of life is an example) the firstborn had special privileges. In some places the first child if a boy (the girls are a separate subject) inherited the estate and there was a set role in society for each succeeding child.
The general Jewish tendency, however, was not to have a fixed slot for anyone: Moses was the leader though not the first child. Other examples of people achieving special status without primogeniture are Levi, David and Solomon.
Is there literature on the first-born syndrome?