First Borns do well with Middles as long as the Middle isn’t a “Challenging Second Born”.  These two complement the other well; Middle children can allow First Borns to take charge and are likely to agree to any adventures that the First Born would like to do.  The Middle needs consistent reassurance that they are loved, the First has the capacity to fulfill that need. In return, the First will enjoy a contented relationship with the peacekeeping Middle.