American birth rates, and a growing population are an important factor in the continued economic success of the world's greatest nation. The population of the United States has continued to grow unlike most other industrialized nations of the world which are typically experiencing birth rate declines. But America is not growing because of birth rates, it is growing because of immigration. Birth rates in America have become pretty anemic as well, and there are a few important reasons that need to be addressed.
For a population not to decline based on birth rates alone, in an industrialized nation, typically a birth rate of 2.1 children per woman is required. There are a lot of factors that play into declining birth rates, and this graph clearly shows that economically bad periods do affect birth rates.
But the economy cannot be the only factor as there was no significant rebound in birth rates in the prosperous decades of the 1980s and 1990s. A lot of that is a result of the typical post-industrialization impacts such as the availability of birth control, women desiring careers, people waiting until later in life to start families so they can complete post-secondary education (consequently having a smaller window to have children) and of course the removal of rationale that if you have more children you have more labor for the farm, a higher likelihood that some will survive to adulthood and a higher likelihood that they will be able to take care of you in your sunset years (besides, the government will do that now).
Each of those reasons merits its own essay. But there is one other reason that I would like to focus on today and that is the oppression of men. Now that may be an overstatement of the situation but with divorce made easy and the deck stacked economically and socially against men in the circumstances of divorce, it's not surprising that there is an evolving aversion to marriage among many men and that certainly is a contributing factor to birth rates in industrialized nations - America being no exception.
This video from the Wall Street Journal with Helen Smith PhD, talks about that very issue. This is a great example of unintended consequences and a specific effect on society.