Why is it that children of older parents (more than 40 years old) are better adjusted, have closer ties with their parents, and are more socially skilled when they enter school than children of younger parents (less than 40 years old)?

Question

Why is it that children of older parents (more than 40 years old) are better adjusted, have closer ties with their parents, and are more socially skilled when they enter school than children of younger parents (less than 40 years old)?
 
Steps of the Scientific Method:
1. Formulation of a hypothesis
2. Choose the research method and design
3. Collect the data
4. Analyze and Interpret the data
5. Report Findings