but essentially he's right - population growth is a serious matter,and it needs to be addressed. Unfortunately there are all kinds of social and cultural factors that influence people when it comes to having children, and it's a very difficult nut to crack in a free society. Twenty five years ago China though it could solve the problem with its 'one child' policy, which ruled that ethnic Han Chinese couples in urban areas could only have one child.
In the first twenty years this policy reduced population growth by around 300 million, and it has certainly had a beneficial impact on the ecology. There have been adverse effects however, and one of them is an abnormally high ratio of men to women in the generation of no-sibling Chinese that is now reaching maturity. The government has recently relaxed the rule for these people, allowing any couple that has no siblings to have two children. This will tend to slow the population decline, but will help to address the male/female imbalance.
Voluntary family size limitation is incredibly difficult to encourage unless there are monetary or social pressures or incentives. Imposing tax penalties on a family that has a third child is one option, as are reductions in benefits. Neither of these sanctions would be popular, but it's difficult to see how to motivate people to voluntarily restrict family sizes.