Answer:
Rate of divorce.
Step-by-step explanation:
The high rate of divorce is a factor that cause family diversity. This behaviours change family and marriage patterns, creating new type of families, single-parent families.
This increasing rate cause a higher single-parent family rate, because more often, men and women think that they are able to raise their children on their own. Moreover, some women just look for a donator and they have their children alone from the beginning.
Therefore, the increasing rate of divorce is a factor.