An article ran yesterday on Yahoo News by Philip Longman examining what he calls The Liberal Baby Bust, the phenomenon that people with secular values are less likely to have children than those with more traditional values.

What's the difference between Seattle and Salt Lake City? There are many differences, of course, but here's one you might not know. In Seattle, there are nearly 45% more dogs than children. In Salt Lake City, there are nearly 19% more kids than dogs.

This curious fact might at first seem trivial, but it reflects a much broader and little-noticed demographic trend that has deep implications for the future of global culture and politics. It's not that people in a progressive city such as Seattle are so much fonder of dogs than are people in a conservative city such as Salt Lake City. It's that progressives are so much less likely to have children.

It's a pattern found throughout the world, and it augers a far more conservative future - one in which patriarchy and other traditional values make a comeback, if only by default. Childlessness and small families are increasingly the norm today among progressive secularists. As a consequence, an increasing share of all children born into the world are descended from a share of the population whose conservative values have led them to raise large families...

This correlation between secularism, individualism and low fertility portends a vast change in modern societies. In the USA, for example, nearly 20% of women born in the late 1950s are reaching the end of their reproductive lives without having children. The greatly expanded childless segment of contemporary society, whose members are drawn disproportionately from the feminist and countercultural movements of the 1960s and '70s, will leave no genetic legacy. Nor will their emotional or psychological influence on the next generation compare with that of people who did raise children.

I have seen this birthrate data in other places, but Longman makes a problematic leap in his framing of a conservative future. His presentation leaves us to believe that values are genetic, and that because of low progressive birth rates, progressive values will be bred out. However, this framework does not account for how progressive values grew out of a culture with traditional values of the early to mid part of the 20th century. There seems to be little guarantee that the many children of conservatives will share their parents' values. If values were genetic, we should expect regular worship participation in the US to rise with population growth, instead, participation has been declining over the last four decades. There will be more children of conservatives, but there might not be more conservatives.