Understand the influence of birth order Learn from the shape of a family Between each birth, the family undergoes a reshaping. The experiences of a first child or an only child are very different from those of a youngest child with three siblings. Each person's position within the family affects the way he or she will think and act as an adult. This updated, new edition includes: What effect your sex and the sex of your siblings has on your birth order characteristics How understanding birth order can make you a better parent and partner Discover how your birth order affects your career