BernardR wrote:I am sorry, Francis. My comment about Testosterone was based on the fact that Germany is now, according to news reports. close to ZPG. In as much as I am not aware of any restrictions on family size in Germany as is done in China, I felt that a natural cause might be pin pointed.
Do you have an explanation of the ZPG situation in Germany, Francis? I would be happy if you would disabuse me. I may have selected the wrong cause.
Such complex situations do not have an unique cause.
One can observe in the nature, how animals adjust population to specific environmental conditions; population relatively to space occupied, availability of food, absence of predators and so on.
That's also, with the obvious adjustments, how human society reacts.
Since decades we observe a decline in fertility rate among the developed countries. This decline is more or less accentuated depending on local and specific factors.
For Germany we can point out overcrowded regions, financial stress at the beginning of a marriage, the fear of losing a job or the stress for finding one, the desire to achieve a career...
The way people see these situations are stained by their local perceptions as, often, they do not travel and experience by themselves.
In addition, they are biased by their local political leaders and commitments.
If you have a moment, Bernard, take a look on this kind of documents:
Population ageing and population decline in Germany