Low Fertility (only one child)
I think you confuse, "Low Fertility", with choosing to not have lots of children...
I don't believe there is a scientific study showing Atheists produce lower sperm counts, or any such indicator of fertility
Since when is having 1 child instead of 5 a bad thing? I don't even see how this is a negative trait
If it were a race to have the most children... anyone with less than 20 children loses, right?
This issue came up earlier
But artificial manipulation of fertility through contraception or other practices would make it only useful if you managed to discount those practices.
Just because an intelligent couple choose to have no children has no necessary meaning to their true "biological fitness"?
Biological Fitness is an empiric not a moral measurement.
There are two accepted empiric measures of biological fitness these are Absolute Fitness and Relative Fitness. Both of these are directly proportional to fertility unless there is a large differences in infant mortality between the groups. As all of the data comes from one country USA there should be no large differences in infant mortality.
Now the case can certainly be made that Biological Fitness is an irrelevant metric. However, it is likely that some readers will feel this metric to be important and that makes the data relevant.
As I mentioned in my response to anon_giraffe fertility rate like biological fitness is an empiric not a moral measurement and its relevance to this discussion can certainly be disputed. There are multiple definitions of fertility. The most relevant is the
Fertility Rate.
Deciding if
sub-replacement fertility is a good or a bad thing is a deep topic and beyond the scope of the the arguments in the opening post. I am content to leave this decision up to the reader but have no objections to anyone who wishes to promote their views on the matter.