A number of different situations can alter sibling relationships, namely three major, universal life events: marriage and having children, divorce and widowhood, and death and family member sickness. 

However, the presence of conflicting studies shows that whether these changes are positive or negative is unknown; the changes vary with the respective siblings, but it is certain that these major life events alter sibling relationships. For example, positive changes in sibling relationships due to a marriage can be due to siblings sharing marriage experiences, and the closeness of the siblings with the spouse. However, sibling relationships can also worsen due to a life changing event such as a marriage. For example, the sibling who is getting married may move away from the family home, or the siblings may not like the spouse or have good relationships with him or her.  

As opposed to marriage, a divorce or widowhood usually increases emotional closeness, contact, and support among siblings. Generally, siblings respond positively to one another’s losses. For this reason divorce, illness in the family, and death of a parent or other family member usually brings siblings closer together as they try to provide support and comfort for each other in times of need.