Just as high taxes and too much regulation impede the creation of new businesses, it also impedes the creation of new children. A responsible parent is less likely to have children when there is uncertainty as to job security and lack of income and whether child can be afforded. There is also the choice between life style and more children. When you have to work harder there is the question as to whether you have the time to raise children as well.
If we want more children then we have to lower taxes and reduce regulation so that people can create the wealth to have more children. Those that are pro taxes are regulation are anti child whether it is intentional or not.