As an (in)fertility physician and ART (assisted reproductive technology) scientific researcher, I found this post fascinating. I agree with your conclusions—sperm counts may or may not be falling in some parts of the world, but unlikely to be contributing significantly to the decline in birth rates. This is also unlikely due to increasing rates of infertility. Most likely the decline in fertility rates is due to widely available effective contraception, increasing wealth, and increasing participation of women in the workforce.
The data also suggest that women are having less children than they ideally would like. I suspect the reasons are largely social ie lack of support such as paid family leave, affordable childcare, etc. But I wonder if there is also a biological component? I am curious about the impact of increasing age of first birth. It is well known that female fertility declines with age. I wonder if rates of secondary infertility (ie infertility while trying to conceive the second or third child) are increasing? I also wonder if making infertility treatment accessible to all and new innovative technologies, such in-vitro gametogenesis that would allow women of advanced age to have genetically-related children, would impact the birth rates significantly?
As an (in)fertility physician and ART (assisted reproductive technology) scientific researcher, I found this post fascinating. I agree with your conclusions—sperm counts may or may not be falling in some parts of the world, but unlikely to be contributing significantly to the decline in birth rates. This is also unlikely due to increasing rates of infertility. Most likely the decline in fertility rates is due to widely available effective contraception, increasing wealth, and increasing participation of women in the workforce.
The data also suggest that women are having less children than they ideally would like. I suspect the reasons are largely social ie lack of support such as paid family leave, affordable childcare, etc. But I wonder if there is also a biological component? I am curious about the impact of increasing age of first birth. It is well known that female fertility declines with age. I wonder if rates of secondary infertility (ie infertility while trying to conceive the second or third child) are increasing? I also wonder if making infertility treatment accessible to all and new innovative technologies, such in-vitro gametogenesis that would allow women of advanced age to have genetically-related children, would impact the birth rates significantly?