Sperm count falling by half over past 100 years?

[Gos_man]

I was perusing the Blogsphere when I came across an article here http://tumeke.blogspot.com/.

In it the blogger has used a claim, (unreferenced I might add), that Human sperm counts have fallen by half over the past century.

Now I am extremely skeptical about these sorts of things but can accept there might be some truth to it. Unfortunately when I Google it I come up with a whole lot of garbage that I am having trouble sifting through.

Does anybody know what the latest accepted scientific view of this is? If so could someone provide a link at all?

[FramerDave]

I would wager that average sperm count would follow very closely the trends as tighty whiteys and boxers come into and fall out of fashion.

[Gos_man]

My thinking is that studies done on sperm counts would have been pretty non-existent 100 years ago. The articles I have seen so far suggest there the starting point sometime in the 1930's. Even these I would think would not be as extensive as thiose conducted in the past 20 to 30 years.

There is the whole question of societal conduct between recording dates as well to consider. Perhaps men ejaculated less often back in the early studies so therefore had higher counts due to that reason.

There are also geographical variations that might influence comparisions. I have read that many of the eartly studies were concentrated in the US but the later ones now include many more locations.

[Bob Klase]

I'm sure that 120 year old men have a sperm count much less than 1/2 of what it was 100 years ago.

[casebro]

But the population has tripled in that time, so the total is actually higher. ;)

[rjh01]

It would be very hard to compare sperm counts from history with today. Techniques change so the results may change. Get a group of men who have not ejaculated recently, their sperm count would be much higher than the general population.

[Soapy Sam]

I know a chap who managed a fertility clinic for years.He seems pretty certain- having looked down a microscope at many samples- that at least in central Scotland, sperm count has fallen sharply in men born after about 1968. He suspects estrogen mimics in diet.
However see this thread for an intriguing new development.
http://forums.randi.org/showthread.php?t=147677