Interesting article about male runners and sex of baby

Runner's &amp Triathlete's Web "File Not Found"

Small study but makes since because of decreased testosterone. Most athletes I know concieved girls. I concieved my first dd when I was running 6 days a week but she was a surprise with one attempt and jump and dump, and always skipped breakfast. So I don't know!
I'm curious what atomic and all the experts thinks, I'm a newbie to all this! I hope it's ok I post this!

Summary:

"To see if running mileage might have a stronger effect than placental burial, Eddie Crawford of the University of Glasgow took a careful look at the effects of weekly mileage, training intensity, paternal age, occupation, and competitive performance on offspring gender in 139 male runners ('Sex Ratio of the Children of Male Distance Runners,' Thesis, Institute of Physiology, University of Glasgow, 1992). Crawford became interested in the topic when a survey appearing in the publication Scotland's Runner revealed that just 23 per cent of the children fathered by runners engaged in serious training were boys.

"Crawford divided his athletes into several categories, including (1) individuals who were not actually training at the time they and their mates conceived a child, (2) subjects who were running between 0 and 30 miles per week when their partners became pregnant, and (3) runners who were training between 30 to 50 miles per week. To these runners, a total of 377 children were born (about 3.4 per man).

"Not running at all - or running less than 30 miles per week - proved to be a good way to increase one's chances of having a male offspring. Overall, about 62 per cent of the children of runners who were taking a break from training or who were running fewer than 30 weekly miles were male.

"However, things changed drastically when weekly mileage soared above 30 miles per week. For those runners who ran between 30 and 50 weekly miles, only 40 per cent of the offspring were gentlemen! According to Crawford, such high-volume running tends to produce dips in testosterone, which in turn produces a decline in the output of boys.

Read more: Do male runners (tend to) conceive girls?

Runner's &amp Triathlete's Web "File Not Found"


Small study but makes since because of decreased testosterone. Most athletes I know concieved girls. I concieved my first dd when I was running 6 days a week but she was a surprise with one attempt and jump and dump, and always skipped breakfast. So I don't know!
I'm curious what atomic and all the experts thinks, I'm a newbie to all this! I hope it's ok I post this!

Summary:

"To see if running mileage might have a stronger effect than placental burial, Eddie Crawford of the University of Glasgow took a careful look at the effects of weekly mileage, training intensity, paternal age, occupation, and competitive performance on offspring gender in 139 male runners ('Sex Ratio of the Children of Male Distance Runners,' Thesis, Institute of Physiology, University of Glasgow, 1992). Crawford became interested in the topic when a survey appearing in the publication Scotland's Runner revealed that just 23 per cent of the children fathered by runners engaged in serious training were boys.

"Crawford divided his athletes into several categories, including (1) individuals who were not actually training at the time they and their mates conceived a child, (2) subjects who were running between 0 and 30 miles per week when their partners became pregnant, and (3) runners who were training between 30 to 50 miles per week. To these runners, a total of 377 children were born (about 3.4 per man).

"Not running at all - or running less than 30 miles per week - proved to be a good way to increase one's chances of having a male offspring. Overall, about 62 per cent of the children of runners who were taking a break from training or who were running fewer than 30 weekly miles were male.

"However, things changed drastically when weekly mileage soared above 30 miles per week. For those runners who ran between 30 and 50 weekly miles, only 40 per cent of the offspring were gentlemen! According to Crawford, such high-volume running tends to produce dips in testosterone, which in turn produces a decline in the output of boys.

Read more: Do male runners (tend to) conceive girls?[/QUOTE]

Runner's &amp Triathlete's Web "File Not Found"

How long do you think a guy would have to keep up a 30-50 mile-per-week running habit to sway pink?

I don't know, I think atomic would know. I was wondering the same thing. I don't know how long it takes to get testosterone down. I didn't run when I conceived my boys. But when I was running I conceived dd. I was running for a
Long time. I looked everywhere about female
Runners and there was no evidence I found only website saying there was no evidence regarding female runners. I have been running 30 plus miles per wk for a month and I am ttc I wish I ran more prior to this but it was maybe 15
To 20 miles. I think it goes back to lack of nutrients and lack of nutrients leads to girls. Male runners decrease testosterone. I'd love to know what the experts say I'm a newbie to all this!!

It takes 2 1/2-3 months for sperm to mature so I would guess that's how long you would have to keep up the running schedule.

Definitely something to consider. My husband likes to run six miles a day when the weather is nice so if it increases your chances that much it might be worth it to TTC. He ran when we were TTC our boys but I don't think he totaled 30+ miles per week. We were both very balanced exercisers at the time: cardio, weights, yoga, lots of hiking. I still exercise (an hour on the elliptical every day and yoga) but I'm much heavier now so I don't know if our combined chances of a girl would be better even with him running that much. But it's something to think about.

Yes I was already aware of this and put that in all my sway plans. It's not just running, it's also cycling (running and cycling by men have been shown in studies to sway pink) and extreme weight training by men(not proven to my knowledge but observationally by many). I am not at all convinced that it is testosterone per se though, because it happens even to guys on the "juice" and they are high in T.

Testosterone was only ever an idea, a theory, and it has NEVER been demonstrated by blood tests. Only personality tests and reviews of other literature.

Runner's Web and Triathlete's Web, a Running, Track and Field and Triathlon Resource Portal for some reason your links aren't working but maybe this one will?

Hmm I've read this too. My husband ran a marathon in October but now only runs around 20 miles per week... As its winter and very cold, he doesn't want to up his mileage until the summer and our first attempt is next week!

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Originally Posted by trifecta

How long do you think a guy would have to keep up a 30-50 mile-per-week running habit to sway pink?

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I don't know and we don't have the data to say.

I want you guys to be careful not to read too much into the sex hormone angle here, don't start thinking "well, how long does it take to get testosterone down" because it may not even BE testosterone. And if it IS testosterone for women (or men) that doesn't mean that it is testosterone for men (or women) if that makes sense. It may be some other thing entirely like the nutz getting warmed up or something we haven't even guessed yet, and so you can't assume that now WOMEN have to start running 30-50 hours a week because that is very, very likely not the case. It may even be (and in fact I'd suspect it) that other men, who are not skilled athletes and probably eating a lot of really good food and so on, could get the same result with a lot less exercise.

One of the biggest pitfalls in this swaying experiment is that people end up getting so consumed by the guesswork, the theories and the hypotheses that we lose sight of just doing what is actually WORKING. We know that women are getting girls just walking, so I don't want anyone to read this and suddenly decide that they have to run 50 miles a week to get a daughter.

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Originally Posted by honeybee37

Hmm I've read this too. My husband ran a marathon in October but now only runs around 20 miles per week... As its winter and very cold, he doesn't want to up his mileage until the summer and our first attempt is next week!

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Does it make any sense though, that there is some magic amount of running a guy has to do?? just becase one study indicated this, there is functionally very little difference between 20 and 30 miles a week. I seriously doubt that at some preset point, 27.49 miles a week or whatever, that is the same for every guy, he suddnely stops making boys and starts making girls. All we know is that running and cycling by DH probably help a pink sway.

As an aside, I read the comments in things like this and people's unbelievable hubris just completely floors me. "This cannot possibly be true, because 30 years ago, I was taught that males determine sex and not females in middle school, and also, Mendel." One definition of stupidity is immediately dismissing people who know more than you as being stupid because you cannot consider new information, and those comments certainly prove this. Hey losers, if a study is showing something different (and the article discusses several studies in it), it's time to POSSIBLY reconsider that you, Online Douchebag #246498, may just simply not be fully informed and there may be something more going on here, ya know, new discoveries, the way those happen??

Atomic - you're so right and it's my silly scientific brain that needs evidence and numbers and all that kind of stuff... I'm so used to precision and detail that it's really hard for me! So please excuse some of my need for detail which j know in my heart of hearts just isn't there :) it's probably why I have two boys!

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Originally Posted by atomic sagebrush

As an aside, I read the comments in things like this and people's unbelievable hubris just completely floors me. "This cannot possibly be true, because 30 years ago, I was taught that males determine sex and not females in middle school, and also, Mendel." One definition of stupidity is immediately dismissing people who know more than you as being stupid because you cannot consider new information, and those comments certainly prove this. Hey losers, if a study is showing something different (and the article discusses several studies in it), it's time to POSSIBLY reconsider that you, Online Douchebag #246498, may just simply not be fully informed and there may be something more going on here, ya know, new discoveries, the way those happen??

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EVERY online source I've read (apart from in here) has some wise guy telling everyone reliably that it's the guy who dictates the sex of the baby. And with it, implies we are all totally dumb by even reading the latest study into it. Makes me so mad!!

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Originally Posted by honeybee37

Atomic - you're so right and it's my silly scientific brain that needs evidence and numbers and all that kind of stuff... I'm so used to precision and detail that it's really hard for me! So please excuse some of my need for detail which j know in my heart of hearts just isn't there :) it's probably why I have two boys!

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No not at all, it was a perfectly sensible question, but it's just that I keep coming back to the common sense of it all which is - just DO what works even if you can't get it exactly at the level what some researcher here or there says, that is probably ok.

I think it's the kind of thing where if your partner already enjoys running and is logging significant miles he might be willing to do a little more (within reason) rather than a little less but I wouldn't expect someone who isn't already a runner to run 30 miles.

This makes sense to me and gives me hope as when DH and I conceived our two boys he was not cycling at all. Yet, when we conceived our DD1 he was cycling to and from work every day 5 days a week. Coincidence? I hope it plays in our favour again for a second DD.

Quote:

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Originally Posted by honeybee37

EVERY online source I've read (apart from in here) has some wise guy telling everyone reliably that it's the guy who dictates the sex of the baby. And with it, implies we are all totally dumb by even reading the latest study into it. Makes me so mad!!

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Exactly!!! It is just so bizarre to see people absolutely dismiss even the remotest possibility that idea might have been wrong or that new information could possibly shed a different light on it - it's actually been a good life lesson really because even experts do it, and it makes one stop and think about if the "expert" saying X, Y, and Z (on any topic) is really informed or they are just spouting the conventional wisdom without questioning it.