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updated 2/5/2013 7:46:52 AM ET 2013-02-05T12:46:52

We'll let you decide which of these TV titles is the most fitting, but a new Harvard study shows the sperm counts of America’s tube junkies are perhaps being pruned by the likes of “2 Broke Girls,” “The Big Bang Theory,” and, yes, “Bones.”

That trio of three of top-rated programs are considered some of the leading semen-sapping culprits, reports the Harvard School of Public Health, which found that men who view more than 20 hours of TV shows weekly have a 44 percent lower sperm count when compared to fellas who watch almost no television. Surely, that daylong visual banquet and chip-and-dipapalooza – a.k.a. the Super Bowl – didn’t help matters. 

Twenty-plus hours per week? Who has so much free time they can devote such a fat chunk of their lives to clicker-clutching couch vegging? Apparently, many of us, said Jorge Chavarro, senior author of the study and assistant professor of nutrition and epidemiology at Harvard.

“It's not difficult to imagine. That’s about three hours a day,” Chavarro said. “Let’s say somebody comes home from work at 7 and turns on the TV; they only need to watch TV until the evening news and they’ve watched three hours.”

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Starting in the 1990s, studies have suggested a reduction in sperm counts among men in various cities, including in Europe and the United States. It’s become more clear in the past six years.

“Most people have speculated these are due to higher use of environmental chemicals,” Chavarro said.

“One of the things that has been overlooked during same six-year period: there also have been vast changes in how people live their lives, including how people eat, watch television, move around – whether they are active or not. Relatively little attention has been paid to these factors (when it comes to sperm counts). We wanted to look at that.”

The researchers examined the semen quality of 189 college men between the ages of 18 to 22 who participated in the Rochester Young Men’s Study during 2009 and 2010 at the University of Rochester in upstate New York. The men were quizzed about their exercise and TV propensities plus their diets, their stress levels and whether they smoked – all of which can impact sperm quality.

Twenty five percent of the 189 men reported logging more than 20 hours per week of TV time, Chavarro said.  Their sperm counts were 44 percent lower than those of the men who watched little television, the researchers report in the British Journal of Sports Medicine. The men who reported exercising 14 hours a week or more – enough to get out of breath – had the highest sperm counts.

A normal sperm count, according to the World Health Organization, is 53 sperm per milliliter of semen, and when a man has below 15 million sperm per milliliter of semen, that’s considered abnormal.

“A growing body of research suggests that if we’re not healthy, our sperm isn’t healthy,” said Dr. Edmund Sabanegh, chair of the urology department at the Cleveland Clinic. “So whether it’s maintenance of healthy body weights or whether it’s diets high in antioxidants, those things are markers for our fertility.”

Doctors are seeing a disproportionate number of obese people as patients in their fertility practices, Sabanegh said. When he talks to his patients, the conversations veer into a variety of lifestyle choices, which can indirectly include TV consumption.

“The folks that tend to watch more television obviously have lower exercise rates,” he said. "Twenty hours seems to be a pretty high amount of TV. You would have to wonder about (the study subjects’) diet habits, their sleep habits, and all sorts of other things that could enter into their fertility.”

Several health factors can mar sperm counts, Sabanegh said. In some overweight men, their endocrine system becomes out of whack, which lowers testosterone. That can lead to lethargy. In addition, they may have oxidative stress, a damaging chemical reaction that can hurt sperm and that runs higher in people who gorge on fatty foods and rarely exercise.

In an increasingly sedentary nation of gamers and dozers – not to mention emailers, YouTubers and Facebookers – why does an overindulgence in TV specifically seem to spoil sperm?

“A lot of research has explored how television viewing increases obesity. One of the important mechanisms appears to be TV watchers are exposed to commercials for food,” Chavarro said. “That makes you hungry and you eat more.”

“No question,” agrees Austin, Texas resident, Jason Jepson, 38, who estimates he watches 35 to 38 hours of TV per week.

“My wife buys me SunChips because they are healthy. But when a commercial for SunChips comes on, I think: You know, that would be pretty good with salsa right now. I find myself eating during part of the show and at the commercial I’m doing 20 pushups, thinking that will take off that bag of SunChips I just downed,” Jepson said.

“The curse of my TV watching is that damn DVR: That thing allows me find more stuff that I think I might want to watch.”

But Jepson balances his TV appetite with two hours per day of exercise. The catch: He likes to watch one hour of television in the morning before he goes for a four-mile run, he said. He also lifts weights over his lunch hour. This exercise thing could be working.

“I got married in September of 2012 and my wife was pregnant in November,” Jepson added. “I am either an anomaly, or the Harvard study may be wrong.”

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