The children may also not share similar interests because of their different developmental levels. The temperament of parent and child will affect the success of the spacing. Easy-going, independent, social children may delight in the arrival of a sibling at any time. High-need, sensitive children may have more of an adjustment to make to the addition of a brother or sister. Further, they may need more adult attention all the time, before and after the sibling comes.
Parental temperament is another key factor.
There are people who easily slip into the role of parenting, fitting naturally into the rhythm and demands of the job as if they had been doing it their entire lives. For these parents, the addition of another baby just makes life richer. For others, who find interrupted sleep, unpredictable schedules and duet crying a challenge, adding another baby can make life feel crazy. Lastly, parental expectations about the sibling relationship make a difference in the success of the family relationships. Parents who have had contentious relations with their own siblings may have a harder time envisioning their own children having close, supportive relationships than parents who have experienced the benefits of lifelong friendships with their own siblings.