It's a true, but misleading statistic.
Being white is not the cause and is not directly related to the falling birth rate.
Being successful is what causes the decline.
The fact that white people are, on average, more successful is why we're less likely to have many children.
A healthy and successful population (of any colour) always declines in numbers.
Sure.
Lack of access to contraceptives is far more of a leading cause.
Source Link
https://www.nytimes.com/2018/06/20/us/white-minority-population.html