I believe so, and it's quite concerning on the one hand, yet unsurprising on the other.
I'm a young man, but I've noticed that even over my short life men have gotten more and more feminine with every passing year. It's little things, from the type of music they listen to, the sudden glorification by many of gays, the disinterest in beer and sports, the sudden interest in telephones and gossip, the obsession with skinny jeans and metrosexual fashion, and a general passive, whining demeanor you didn't see even 10 years ago.
Then I ran in to this report, which shows that blood tests show average testosterone levels for men are down by 20% since the 80's, and it's not age related. That's a significant decline.... but it makes sense. Look at how men acted in the 80's compared with today.
As Reuters reported in 2006:
A new study has found a “substantial” drop in U.S. men’s testosterone levels since the 1980s, but the reasons for the decline remain unclear. This trend also does not appear to be related to age.
The average levels of the male hormone dropped by 1 percent a year, Dr. Thomas Travison and colleagues from the New England Research Institutes in Watertown, Massachusetts, found. This means that, for example, a 65-year-old man in 2002 would have testosterone levels 15 percent lower than those of a 65-year-old in 1987. This also means that a greater proportion of men in 2002 would have had below-normal testosterone levels than in 1987.
“The entire population is shifting somewhat downward we think,” Travison told Reuters Health. “We’re counting on other studies to confirm this.”
Travison and his team analyzed data from the Massachusetts Male Aging Study, a long-term investigation of aging in about 1,700 Boston-area men. Data from the men were collected for three time intervals: 1987-1989, 1995-1997, and 2002-2004.
The researchers observed a speedier decline in average testosterone levels than would have been expected with aging alone.
It’s likely that some sort of environmental exposure is responsible for the testosterone decline, Travison said, although he said attempting to explain what this might be based on the current findings would be “pure conjecture.”
Men’s Health wrote in 2007:
In the summer of 2006, Travison attended an Endocrine Society meeting where another researcher, Antti Perheentupa M.D., Ph.D., from the University of Turku, in Finland, presented evidence of a similar decline. The Finnish results suggested the change was happening among younger men, too. A man born in 1970 had about 20 percent less testosterone at age 35 than a man of his father’s generation at the same age. “When I saw another group reproducing our results,” says Travison, “that was convincing to me that we were seeing a true biological change over time, as opposed to just some measurement error.”