The Decline In Male Fertility
online.wsj.com
online.wsj.com
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 :)
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?
"around the time of ovulation, a healthy female body produces a particular cervical mucous that creates a protective, hospitable environment for sperm"
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!
I see what you did there. 8-)
This is due to the vagina being a generally hostile environment for sperm (evolution is funny like that).
But I don't understand how having more is like having a bigger engine. Are they working collectively?
Although most people see sperm as a "race", several of the barriers (specially, the "shell" of the female gamete) need several sperms working on it at once.
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.
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).
Also - related point - for IVF, they have very strict quality standards. Using the measurement standards for IVF would consider 15% "normal forms" as an acceptable level.
Some traits are linked to a single gene, but most of them, aren't. (and to make stuff more confusing, a single gene might affect several traits at once).
I would take the risk to make sure my children do not inherit known bugs.
Oh, and you have to do it in production, and it's a critical system where people die if you get it wrong.
Why not replace all faulty genes with known good ones? In homozygote cases, you can replace one of two copies with good version.
One could argue that your diet and lifestyle could've caused that, and it's hard to counter. (I have -4 vision, by the way.) I don't think medde's comment adds much to the discussion, but I can see the point about our inability to “understand nature”. We don't know what we don't know.
I think he chose a benign example, but I'm sure everybody is aware of birth defects.
I don't want to "understand nature", I don't want to change my lifestyle, I just want it to be fixed, next generation getting the good parts.
I remember a study not long ago that found sedentary lifestyle drastically affecting chances of death from cardiovascular disease. It does seem plausible to me that there could be many more things that affect us in more subtle and unexpected ways. Posture, thinking patterns—those little habits. Two apparently similar lifestyles may actually turn out to be very different when analyzed to such fine detail.
And since children from early age imitate their parents, it's natural to expect those things to get passed (with certain variance) from generation to generation.
Now the above is very unscientific, of course. I don't deny that genetics matter—just that there might be other things that matter as well.
Analogies from software engineering world are often flawed, but I'll draw one: a shallow fix of an annoying bug without full understanding of a complex system (and decent test coverage) leading to perplexing problems down the line—I think it's a familiar situation.
Most of your short comment is good vs. bad judgement (nature is great, gene selection and cloning are evil). It provoked guard-of-terra's reply, which states the obvious—yes, nature isn't ‘great’ (neither is it ‘evil’, it simply is), and gene selection can be useful—wouldn't we all like to be able to ‘fix bugs’ in humans. I was compelled to reply to it for some reason, but regret that now.
FWIW, I didn't downvote or upvote your comment, and only now have noticed that it's greyed.
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 :)
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...
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?
3 weeks later and we find out the study was somehow horribly flawed.
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.
http://medicalmarijuana.procon.org/sourcefiles/UMPMC-quarter...
Check out Table 2. (Seized) marijuana from the late 2000s has 10x as much THC as that from the mid-1970s.
It's legal for me to smoke, but I don't. Ten years ago it wasn't, but I could have if I were inclined. I don't think that legalization efforts or the like are really increasing the number of people who smoke, either you want to and did regardless, or you don't anyway.
Maybe there was a temporary drop in the number of smokers before the kids that grew up on D.A.R.E. learned how to use the internet (and subsequently learned that no, pot won't kill you with just one hit...), but otherwise I would hesitate a guess that we are still around 1960's level consumption.
http://science.howstuffworks.com/marijuana5.htm
http://www.420magazine.com/forums/cannabis-facts-information...
also watch http://www.imdb.com/title/tt1039647/
> Smoking cannabis is a double whammy, because tobacco
What? You can smoke cannabis without tobacco.
calm down, it's a common suggestion that THC levels are rising and rather than just repeating it I asked if it is, in fact true. A simple "no" is better.
Your first link does not support your point as strongly as you seem to think. Your second link is obviously a joke - no one would present such an obviously biased source with so many cherry picked reports seriously.
Wait, what? I don't follow you. That's like saying frying bacon is a double whammy, because frying eggs is a leading cause of stuff getting stuck to your frying pan.
[http://ivf.net/ivf/daily-sex-helps-to-reduce-sperm-dna-damag...]
http://www.wisconsinwatch.org/2013/05/22/study-chemical-blen...
http://www.sciencedaily.com/releases/2009/01/090118200636.ht...
source: http://ivf.net/ivf/daily-sex-helps-to-reduce-sperm-dna-damag...
Think I'm joking? There are studies proving an inverse correlation between education and number of progeny.
Either way, what's causing infertility is quite obvious - economic prosperity does.
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.
Why would it affect sperm count but not longevity?
Basically, people/genes that would have died out are being helped to continue in the gene pool.
BTW have my third kid due in a couple of months. So survival of the fittest is working out fine for me.
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.
IOW, you'd need to blind the experiment.
If I germinated a plant sprout in my room near a wireless router, would you stop going around making this claim?
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.)
This isn't a joke.