What Happens When a Stepfather Enters the Family

What happens when a stepfather enters the family?

A) The psychological health of the family improves dramatically.
B) There is essentially no difference in family relations. Whether the family was operating at a low or high level, it continues to do so.
C) Often the children in the family begin having serious issues including lower self-esteem and great behaviour problems.
D) The mother's happiness increases, which is then followed by an increase in the children's happiness.