So a child born third in a family constellation but whose next older sibling is seven years older, may develop first-born tendencies. The first born of any gender is more likely to take on first-born characteristics. Sometimes work or chores are assigned based on sex. In a very traditional home the oldest male usually gets the manly chores such as cutting the lawn, digging weeds, hauling trash, and helping Dad. The physical makeup of the children can turn birth order upside down or at least tilt it a bit sideways.
Twins are often an interesting mix of competitor and companion.
In a family constellation, twins are bound to cause pressure, especially on any children born after them. Why You Are the Way You Are . Dell Publishing, pp. The following paragraphs on birth order variables are taken from Leman, pp. 1 Firstborns may be more highly motivated to achieve than their younger siblings or may choose professions such as science, medicine, or law.