In reality, no race, religion or political group needs to have fewer kids to reach a zero population growth. They just need to be responsible and wait until they are older to have those kids.

If you look at the equasion for birthrate and population growth, the length of time between a person's birth and the age that person starts to have children is the most important single multiplier. Besides, children born to 28 year olds are more likely to be happy, well-adjusted and properly cared-for. Everbody wins as does the environment.