Sperm Count in Western Men Has Dropped Over 50 Percent Since 1973, Paper Finds

The phathalates hypothesis sounds plausible to me. However, it will be a combination of factors social, economical and biological. One hypothesis, I have been thinking of is about relation between the age of the father when the child was conceived and it's correlation with sperm count of the child when he grows up.

I am not sure if this data was collected in the study. Does anyone know about any such study?

Economic changes can probably be tracked back to Stagflation[1] and the 1973 Oil Crisis[2], and the associated rise of Neoliberalism as evidenced, early on, through the Nixon Crisis[3] and formation of the Trilateral Commission[4]. Of course there was a huge amount of social change going on at the same time, much of which was interrelated with the economic changes.

As an example of how some viewed these challenges, the Trilateral Commission's 'Crisis of Democracy' paper[5] - though heavily criticised from both sides of politics[6] - offers some interesting insight into the perspectives held by a number of highly influential people of the period.

[1] https://en.wikipedia.org/wiki/Stagflation#Explaining_the_197...

[2] https://en.wikipedia.org/wiki/1973_oil_crisis

[3] https://en.wikipedia.org/wiki/Nixon_shock

[4] https://en.wikipedia.org/wiki/Trilateral_Commission

[5] http://trilateral.org/download/doc/crisis_of_democracy.pdf

[6] https://en.wikipedia.org/wiki/Trilateral_Commission#Criticis...

Quote from article (meant as response to AndrewKemendo): "Phthalates are a group of chemicals used to make plastics more flexible and harder to break. In several studies over the last two decades, they have been shown to disrupt the operation of male hormones like testosterone and have been linked to genital birth defects in male infants.

Dr. Swan, who conducted a 2008 study about phthalate exposure, said that scientists have had the ability to measure exposure to plasticizers only since about 2000, via urine. That has led to a 20-year lag in the process since researchers cannot enroll men to produce sperm until they are in their 20s.

That evidence is the “missing piece of the puzzle,” she said."

Here in the Netherlands several partie are trying ot get hormone disturbing substances on the political agenda but even BPA is apparently not even illegal here. There was even a show where they measured BPA in the urine of politicians and still, very little attention is given to such substances. [0]

[https://radar.avrotros.nl/uitzendingen/gemist/14-11-2016/hor...]

There is an argument that the problems people see with both 'real wage stagnation' and 'increased divorce rates' are really problems caused by measuring the wrong thing.

The argument is quite clear when it comes to the divorce rate; Being alone, if financially tenable, is better than being in a bad relationship, so if you make being alone financially tenable for another half of the population, divorce rates will go up, and in that case, it becomes quite difficult to argue that increased divorce rates are bad. In fact, one could argue the opposite, that increased divorce rates indicate people being able to leave unpleasant relationships.

The argument is a lot less clear for wages. The strongest argument, I think, is that if you are measuring average per worker pay, women on average make less than men, and thus you will get a lower rate for 'average worker' than for 'average male worker' - even today, those numbers are stark, and before the 1970s, your 'average worker' demographics looked a lot more like what you'd see in today's "average male worker" statistics; I think you'll find that 'average male pay' has climbed rather a lot more than 'average pay'

The other argument, I think, is a lot weaker; if you double the number of workers, some would argue, you will naturally depress wages. (Of course, others would argue that the secondary effects of having more workers in an economy would make the economy more wealthy and drive wages up overall.)

In particular, the article says:

"In a Harvard study published last year in the journal Human Reproduction, Jorge E. Chavarro, M.D., Sc.D., and his colleagues found a strong association between men’s consumption of soy foods and decreased sperm counts."

The study in question seems to be this:

https://academic.oup.com/humrep/article/23/11/2584/2913898/S...

"The intake of 15 soy-based foods in the previous 3 months was assessed for 99 male partners of subfertile couples who presented for semen analyses to the Massachusetts General Hospital Fertility Center. ... There was an inverse association between soy food intake and sperm concentration that remained significant after accounting for age, abstinence time, body mass index, caffeine and alcohol intake and smoking. In the multivariate-adjusted analyses, men in the highest category of soy food intake had 41 million sperm/ml less than men who did not consume soy foods." (For reference, various sources say anywhere from 20 to 150 million sperm/ml is average.)

Contrariwise, the Wiki article on soy points to this meta-study (from four years before the above):

https://www.ncbi.nlm.nih.gov/pubmed/20378106

"Clinical evidence also indicates that isoflavones have no effect on sperm or semen parameters, although only three intervention studies were identified and none were longer than 3 months in duration."

Here's another from a few months after the meta-study:

https://www.ncbi.nlm.nih.gov/pubmed/19819436

That last one seems to be a randomized controlled study, where they gave a bunch of college men either milk protein or one of two variants of soy protein.

I don't know if there's anything in soy that isn't in the "soy protein isolates" from the last study. If there isn't, then the last study seems like strong evidence. The first one could conceivably come down to some sort of selection bias.