> In general, men produce upward of 60 million sperm per milliliter of semen. ...But below that threshold and particularly under about 20 million per ml, their ability to help conceive drops. It may take a couple longer than a year to conceive...
I can't even intuitively understand how going from 60 million to 20 million would make any difference at all. There are millions there, you know.
I can understand how dropping by 99% might affect things, but how on earth could a drop of 2/3 result in taking a year???
Fertilization is actually an accretive process. While only a single sperm will actually fertilize the egg, a single lone sperm is not capable of accomplishing the task. The ovum has a layer of protection that prevents access. Sperm cells, in turn, have some sort of enzyme payload that breaks down this barrier. It takes a lot of this enzyme before the barrier is weakened enough for a sperm to gain access. Not enough sperm, no one's getting through.
Additionally, the female reproductive tract is generally a hostile environment. This is by design, in order to weed out sperm cells with defects. Since this is a biological system, you're going to have some variation and some females are going to have a lower sperm survival rate than others. I have no idea what the range is, but I would be entirely unsurprised to learn the variation spreads over several orders of magnitude.
Sperm counts are just the start. Motility and morphology are also factors. Motility is the percentage that can swim forward. Morphology is the percentage that are normally shaped. Using the widest ranges, normal morphology is 40% or better, and normal motility is 25% or better.
So, the total count only tells us so much. The number that are actually suitable for conception are a subset of the total, and if the total goes down, the subset becomes smaller.
The lower the number of quality sperm, the harder pregnancy becomes. Contra other commenters in this thread, the extra time this requires is probably not a linear function but geometric. At a certain point, outside intervention is most likely required (IUI/IVF).
Well, the uterus is a pretty caustic environment for sperm to be in. I have no specialized knowledge about this topic, but my guess would be that a large percentage of sperm don't make it to the egg, and so a drop of 2/3 would reduce the probability of a few making it that far by a lot.
It takes, on average, 3 months for a healthy couple to conceive. If the limiting factor is the number of sperm, then it would take 3 times as long if you produce 1/3 the sperm. That's nine months, but it could conceivably take over a year.
Maybe a couple that bones 4 times per month (a lot of couples are this way), some percent of the time with success... Well if the average sex has a 10% chance of inducing pregnancy (this is perhaps the case for certain pairs more than others), then it will take, on average, 2.5 months to get pregnant.
Perhaps the 2/3 drop plays out linearly (since it's simply remarkably rare that a sperm gets thru to the egg...
Suddenly it might take an average of 7.5 months. If this is the case you suddenly have far more couples giving up, separating etc. Perhaps it's a bigger deal than we imagine.
I agree tho: you'd think it'd almost be a plus... less need for birth control! win!
WSJ desperately trying to suggest multiple causes to sidestep blaming the obesity epidemic. Reading between the lines that sounds a lot more correlated with the trend than what I would assume is pretty consistent pot usage over the last, say, 50 years.
EDIT: remember, the idea isn't to figure out what causes reduced male fertility, it's to see which of those causes correlates best with the observation.
EDIT 2: of course by the same logic, sugar intake is what's causing the obesity epidemic (the fatty foods comment in the article is unimpressive)
EDIT 3: DanBC, excellent point about THC concentration. I didn't think of it. I can't find any data about consumption, nor am I committed enough to the subject to dig for it :)
There are a few studies showing links between cannabis use and infertility in men. Smoking cannabis is a double whammy, because tobacco use is a leading cause of erectile dysfunction.
> what I would assume is pretty consistent pot usage over the last, say, 50 years.
That's a big assumption. I'd be interested to see any numbers to support it. Certainly in the UK it feels like people smoke more, smoke more often, and start earlier. But I don't have any numbers, this is just my opinion. I'd also be interested to see if modern cannabis actually is stronger than cannabis used in the 60s, 70s, 80s, etc.
I could understand correlation with obesity, but correlation with "high-fat diets" just seems misleading and irresponsible.
I mean, presumably most of whatever correlation there is is coming from their level of obesity. They want me to believe that something like the paleo diet, of all things, is supposed to reduce sperm count in people of healthy weight?
I'm surprised that the article doesn't mention environmental causes. It's been known for a while that almost all water involved in human activities is polluted and contain residues of pharmaceutical drugs, pesticides and other things. It's been shown that they mess with fish sexual functions, and they are strongly suspected as a cause for the decline of human male fertility.
"Young men's marijuana use is linked to decreased sperm count, but not alcohol or cigarettes."
Wow that's actually kinda nuts. I have no idea why on earth they would even bring alcohol and cigs into the mix. This is on the edge of saying smoking and drinking is absolutely OK.
I guess booze has a pretty high chance of giving you kids you never knew about...
Since frequency of emission leads to sperm count changes, it would be interesting to see a plot of sperm count against easy availability and societal acceptance of porn.
It would be interesting, bu migh not relevant in regard of fertility.
Sperm count decreases, but sperm health increases and the consensus is that daily ejaculation sould be OK
Given that we have 7 billion people on the planet and climbing, we definitely do need to figure out what's causing the infertility so we can promote it throughout the world.
Actually when you apply the correlation between rising income levels and lowering reproduction rates to the projections of rising incomes of those who are now poor and reproducing at (relatively) high rates, global population is expected to start falling in as little as 20 years (admittedly this is a political topic and these is a wide range of projections available, including many who foresee an increase to 15 or 20 billion in 100 years).
Either way, what's causing infertility is quite obvious - economic prosperity does.
I've been writing up a blog post on the subject of extinction for a little why now and my theory is essentially this happening. Mankind could theoretically go extinct because we get to a point where we can no longer naturally reproduce. Sure science in reproduction has come a long way, but because it's a manual and drawn out process, I don't think science could even remedy reproduction issues faster than the population starts to decline.
Is it really a surprise sperm rates are lowering given the number of chemicals in our food, pollution and exposure to hazardous materials on a daily basis? Sperm counts aren't the only factors in reproduction but rather environment variables also play an important part in the process. What we eat, what we breath and how we live are also other serious factors and given the modern diet is anything but nutritional for a lot of people, it spells disaster in the long run.
Reading an article like this kind of scares me. Because it kind of gives what I've been debating internally inside of my head for the last few weeks. The day we stop being able to naturally reproduce is the day mankind is in some serious trouble.
> Is it really a surprise sperm rates are lowering given the number of chemicals in our food, pollution and exposure to hazardous materials on a daily basis?
Why would it affect sperm count but not longevity?
I love how everyone is so worried about male fertility and how it is referred to as a sperm count 'crisis'.
The real elephant in the room which is never spoken about is overpopulation of our planet. This is far bigger problem and in my opinion, any slight percentage drop in male fertility would be a blessing in disguise!
Plant sprouts won't germinate when placed near a wireless router. Also sleeping with a cell phone next to your head apparently affects concentration the next day.
> Also sleeping with a cell phone next to your head apparently affects concentration the next day.
Students "noticed". Which means nothing. Measuring focus and concentration is a well studied field, we have excellent tests for doing that. It would be VERY simple to properly measure the impact on sleeping next to a cellphone and concentration.
Other things that could come into play: Talking/Texting on a cellphone late at night before sleeping means less sleep or the possibility of less quality sleep, impacting concentration the next day.
Oh, and also what was eaten for breakfast on a given day.
(Reading up more, the plant based one looks like it wasn't done horribly, but there are way too many variables. Unfortunately the reports are not in English so it is hard to find a good analysis of them.)
> Plant sprouts won't germinate when placed near a wireless router. Also sleeping with a cell phone next to your head apparently affects concentration the next day.
If I germinated a plant sprout in my room near a wireless router, would you stop going around making this claim?
No disrespect to the students involved, but that experiment has not been reproduced in a rigorous test environment as far as I'm aware. It would be an extraordinary result so I would be disinclined to accept it without extraordinary evidence.
>that we've removed ourselves from so many evolutionary selective pressures.
we can't remove ourselves from evolutionary selective pressures. Some old go away, some new come, ie. the nature of such pressures just change, yet the selection continues. And as result there will always be the "fittest" specimen, it will just look and behave differently than the one for the previous version of selective pressures.
>the mean of our reproductive ability will drop.
with IVF, cloning, etc... that specific selective pressure may go away. On the other side - the ability to make money to pay for the best set of genes would make for nice new selective pressure.
[+] [-] radicalbyte|12 years ago|reply
When my wife and I had trouble getting pregnant, I was tested twice.
In the first test, my count of live critters was under the minimum threshold. In the second test, the count was at the top of the range.
All other variables were the same (time between production/delivery, time between previous production and test production and volume).
Oh, and we're expecting our first kid in 8 weeks :)
[+] [-] wavefunction|12 years ago|reply
[+] [-] crazygringo|12 years ago|reply
I can't even intuitively understand how going from 60 million to 20 million would make any difference at all. There are millions there, you know.
I can understand how dropping by 99% might affect things, but how on earth could a drop of 2/3 result in taking a year???
Does anyone know of an explanation?
[+] [-] lmkg|12 years ago|reply
Additionally, the female reproductive tract is generally a hostile environment. This is by design, in order to weed out sperm cells with defects. Since this is a biological system, you're going to have some variation and some females are going to have a lower sperm survival rate than others. I have no idea what the range is, but I would be entirely unsurprised to learn the variation spreads over several orders of magnitude.
[+] [-] lmg643|12 years ago|reply
So, the total count only tells us so much. The number that are actually suitable for conception are a subset of the total, and if the total goes down, the subset becomes smaller.
The lower the number of quality sperm, the harder pregnancy becomes. Contra other commenters in this thread, the extra time this requires is probably not a linear function but geometric. At a certain point, outside intervention is most likely required (IUI/IVF).
[+] [-] Centigonal|12 years ago|reply
[+] [-] freyr|12 years ago|reply
[+] [-] redwood|12 years ago|reply
Perhaps the 2/3 drop plays out linearly (since it's simply remarkably rare that a sperm gets thru to the egg...
Suddenly it might take an average of 7.5 months. If this is the case you suddenly have far more couples giving up, separating etc. Perhaps it's a bigger deal than we imagine.
I agree tho: you'd think it'd almost be a plus... less need for birth control! win!
[+] [-] medde|12 years ago|reply
[+] [-] 3am|12 years ago|reply
WSJ desperately trying to suggest multiple causes to sidestep blaming the obesity epidemic. Reading between the lines that sounds a lot more correlated with the trend than what I would assume is pretty consistent pot usage over the last, say, 50 years.
EDIT: remember, the idea isn't to figure out what causes reduced male fertility, it's to see which of those causes correlates best with the observation.
EDIT 2: of course by the same logic, sugar intake is what's causing the obesity epidemic (the fatty foods comment in the article is unimpressive)
EDIT 3: DanBC, excellent point about THC concentration. I didn't think of it. I can't find any data about consumption, nor am I committed enough to the subject to dig for it :)
[+] [-] DanBC|12 years ago|reply
There are a few studies showing links between cannabis use and infertility in men. Smoking cannabis is a double whammy, because tobacco use is a leading cause of erectile dysfunction.
> what I would assume is pretty consistent pot usage over the last, say, 50 years.
That's a big assumption. I'd be interested to see any numbers to support it. Certainly in the UK it feels like people smoke more, smoke more often, and start earlier. But I don't have any numbers, this is just my opinion. I'd also be interested to see if modern cannabis actually is stronger than cannabis used in the 60s, 70s, 80s, etc.
[+] [-] crazygringo|12 years ago|reply
I could understand correlation with obesity, but correlation with "high-fat diets" just seems misleading and irresponsible.
I mean, presumably most of whatever correlation there is is coming from their level of obesity. They want me to believe that something like the paleo diet, of all things, is supposed to reduce sperm count in people of healthy weight?
[+] [-] epsylon|12 years ago|reply
http://www.wisconsinwatch.org/2013/05/22/study-chemical-blen...
http://www.sciencedaily.com/releases/2009/01/090118200636.ht...
[+] [-] fein|12 years ago|reply
Wow that's actually kinda nuts. I have no idea why on earth they would even bring alcohol and cigs into the mix. This is on the edge of saying smoking and drinking is absolutely OK.
I guess booze has a pretty high chance of giving you kids you never knew about...
[+] [-] darkarmani|12 years ago|reply
[+] [-] 300bps|12 years ago|reply
[+] [-] hrktb|12 years ago|reply
source: http://ivf.net/ivf/daily-sex-helps-to-reduce-sperm-dna-damag...
[+] [-] mullingitover|12 years ago|reply
[+] [-] xentronium|12 years ago|reply
[+] [-] roel_v|12 years ago|reply
Either way, what's causing infertility is quite obvious - economic prosperity does.
[+] [-] DigitalSea|12 years ago|reply
Is it really a surprise sperm rates are lowering given the number of chemicals in our food, pollution and exposure to hazardous materials on a daily basis? Sperm counts aren't the only factors in reproduction but rather environment variables also play an important part in the process. What we eat, what we breath and how we live are also other serious factors and given the modern diet is anything but nutritional for a lot of people, it spells disaster in the long run.
Reading an article like this kind of scares me. Because it kind of gives what I've been debating internally inside of my head for the last few weeks. The day we stop being able to naturally reproduce is the day mankind is in some serious trouble.
[+] [-] EdiX|12 years ago|reply
Why would it affect sperm count but not longevity?
[+] [-] gadders|12 years ago|reply
Basically, people/genes that would have died out are being helped to continue in the gene pool.
[+] [-] lettergram|12 years ago|reply
[+] [-] qubitsam|12 years ago|reply
[+] [-] deepvibrations|12 years ago|reply
[+] [-] everettForth|12 years ago|reply
[+] [-] shirro|12 years ago|reply
BTW have my third kid due in a couple of months. So survival of the fittest is working out fine for me.
[+] [-] ChrisNorstrom|12 years ago|reply
http://www.dr.dk/Nyheder/Indland/2013/05/16/131324.htm
Plant sprouts won't germinate when placed near a wireless router. Also sleeping with a cell phone next to your head apparently affects concentration the next day.
[+] [-] com2kid|12 years ago|reply
The area next to my wireless router is so hot it is uncomfortable to touch. How near is near?
Oh and also, the plant sprouts germinated just fine. The media misreported the living hell out of things. Pictures can be found in the pdf@ http://www.dr.dk/NR/rdonlyres/075641A4-F4D4-4ECF-834F-C0DAF2...
The seeds next to the router did grow slower.
> Also sleeping with a cell phone next to your head apparently affects concentration the next day.
Students "noticed". Which means nothing. Measuring focus and concentration is a well studied field, we have excellent tests for doing that. It would be VERY simple to properly measure the impact on sleeping next to a cellphone and concentration.
Other things that could come into play: Talking/Texting on a cellphone late at night before sleeping means less sleep or the possibility of less quality sleep, impacting concentration the next day.
Oh, and also what was eaten for breakfast on a given day.
(Reading up more, the plant based one looks like it wasn't done horribly, but there are way too many variables. Unfortunately the reports are not in English so it is hard to find a good analysis of them.)
[+] [-] diminoten|12 years ago|reply
If I germinated a plant sprout in my room near a wireless router, would you stop going around making this claim?
[+] [-] jl6|12 years ago|reply
[+] [-] WalterSear|12 years ago|reply
[+] [-] tomjen3|12 years ago|reply
[+] [-] guttermaw|12 years ago|reply
IOW, you'd need to blind the experiment.
[+] [-] unknown|12 years ago|reply
[deleted]
[+] [-] unknown|12 years ago|reply
[deleted]
[+] [-] VladRussian2|12 years ago|reply
we can't remove ourselves from evolutionary selective pressures. Some old go away, some new come, ie. the nature of such pressures just change, yet the selection continues. And as result there will always be the "fittest" specimen, it will just look and behave differently than the one for the previous version of selective pressures.
>the mean of our reproductive ability will drop.
with IVF, cloning, etc... that specific selective pressure may go away. On the other side - the ability to make money to pay for the best set of genes would make for nice new selective pressure.
[+] [-] piptastic|12 years ago|reply
[+] [-] Ygg2|12 years ago|reply
[+] [-] Qantourisc|12 years ago|reply
[+] [-] McUsr|12 years ago|reply
This isn't a joke.
[+] [-] Tycho|12 years ago|reply
[+] [-] atestu|12 years ago|reply
[+] [-] eeky|12 years ago|reply
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