You and your spouse have one wonderful daughter and you are trying to decide if you should have another child. On the one hand, you are quite content with your daughter

On the other hand, your spouse is afraid that your daughter will be selfish, spoiled, and self-centered if she is an only child. Based on what you know about only children, what would you tell your spouse?
What will be an ideal response?

A good answer will be similar to the following:
The research shows that only children are better off in many ways than children with siblings. In no case were only children worse off in comparisons of achievement, intelligence, and character. In fact, only children had higher levels of achievement, higher intelligence, greater leadership, autonomy, and maturity. Only children seem to benefit considerably from a lifetime of exclusive parental attention.