Doggie style has higher odds to have a boy.
Doggie style has higher odds to have a boy.
present wrote:
the facts wrote:
"Perhaps, the strongest link between mothers and offspring gender has been discovered in women who suffer from toxaemia in pregnancy."
The mom does NOT play a role in determining sex of offsrping. All eggs provided by the mom carry an X chromosome. If a sperm carrying an X chromosome fertilizes the egg, the sex will be female. If a sperm carrying a Y chromosome fertilizes the egg, the sex will be male. The dad determines the sex.
Except that:
1) Occasionally mothers spontaneously abort (miscarry), and there is evidence that under certain conditions these miscarriages are more likely to affect one sex than the other.
2) Though the father's sperm do indeed determine the sex of the foetus, there is evidence that the mother can provide an environment that is more "welcoming" to sperm of one sex than to sperm of the other sex.
Both of which mean that, under certain circumstances, it is entirely conceivable (sorry) that mothers play a role in determining a child's sex.
And also:
3) The Trivers-Willard hypothesis in evolutionary biology explains deviations from 50:50 birth sex ratio in mammals based primarily on the mother's physical condition (nutrition, body fat, disease status, etc). Basically, if the mother is in good condition she's slightly more likely to have a son, because she can allocate a lot of resources both during and after birth to maximize his overall condition and thus make him a more competitive mate over poorer condition males. If she's in poor condition, the mother is more likely to have a daughter because daughters, regardless of their condition, can usually find a mate.
I'm not sure if the mechanism has been definitively determined, but I think it has something to do with spontaneous abortion of male embryos in poor condition mothers by cutting off nutrients during very early growth.
I'll leave you vultures to decide whether you think male distance runners are more likely to have female partners who are of better (more sons) or poorer (more daughters) physical condition than average.
present wrote:
1) Occasionally mothers spontaneously abort (miscarry)
Not occasionally -- very frequently. It's estimated that up to 40% of all human fertilized eggs/embryos/fetuses spontaneously abort, about half of which for no clear reason (i.e. no genetic or growth abnormalities). Hard to measure directly because so many spontaneous abortions happen before a women has any evidence that she's pregnant.
I've noticed this trend amongst lawyers as well, regardless of whether or not they run.
Men don't conceive girls. Women with a uterus and functioning ovaries conceive children.
That means that male runners (esp from CT) who pretend to be women will never conceive children. Are you even in high school yet because this should have been taught in biology?
Flounder wrote:
Men don't conceive girls. Women with a uterus and functioning ovaries conceive children.
That means that male runners (esp from CT) who pretend to be women will never conceive children. Are you even in high school yet because this should have been taught in biology?
The current year is 2019. To still believe in what you just said is bigotry.
Post of the year.
Current year is 2019 wrote:
Flounder wrote:
Men don't conceive girls. Women with a uterus and functioning ovaries conceive children.
That means that male runners (esp from CT) who pretend to be women will never conceive children. Are you even in high school yet because this should have been taught in biology?
The current year is 2019. To still believe in what you just said is bigotry.
zxczxcv wrote:
Killermike, you bring some good stuff here, but you seem to think that by calling careful self-observation and reporting "anecdotes" you show that it is useless and tells us nothing. However, a) most research studies involving exercise are small in number and often problematic in many ways, leading to contradictory claims, and b) the high mileage runners are a select group and hard to get into a study, so this provides a good start. If there's no lab coat, that doesn't mean we do not observe and report as well as or better than and certainly more punctually than the study authors. For instance, we might wait years for the report to conclude something about achilles drops or try it out and see what works. The practitioners get it right long before the study authors who generally don't know much about what they are doing. Also, if you see trends in reports, then that gives researchers a good question to examine.
"Careful observation" by a person who isn't engaged in a formal study with an intentional design is still just an anecdote. And the inability to craft a good study to measure this doesn't mean that anecdotes are suddenly good at measuring it.
No there is no way in hell that the readers of this forum are as good at solving this problem as actual researchers doing studies. This is totally unlike questions such as "Which shoe is best?" That is a qualitative thing that one person can test for themselves. Rather, this question is more along the lines of "If we lined up 1,000 random offspring of high-mileage runners, would the number of boys total 500 or just 450? Forum posts are of no value in answering those kinds of questions -- for all sorts of reasons, starting with confirmation biases and respondent self-selection.
You are correct. LetsRun merely exists for entertainment. Any similarity to real life is purely coincidence.
Two-time Olympic marathoner Ed Eyestone has, I believe, 6 daughters and no sons. He said everyone in his training group had only daughters as well. I think there is a hypothesis about body temperature during extended periods of training and how it affects Y chromosome sperm more than X?
When I was running 100+ miles a week we had a girl.
When I was lifting like a boss, put on 30+ pounds, eating eggs everyday, we had a boy.
Coincidence I think not!!!
Alan
We had 3 boys running 100-140mpw for 5 years so I don't believe it.
Depends how fast they are running. I do know that fighter pilots that break the sound barrier in flight reduce their male sperm and are more likely to father girls.
xxxxx wrote:
Depends how fast they are running. I do know that fighter pilots that break the sound barrier in flight reduce their male sperm and are more likely to father girls.
I believe the connection between lower sperm count and an increased likelihood of fathering girls is relatively new and not that strong. I found a study from 2011 that said it was the first study to show such a link, and the drop in male offspring production was only from 51.5% to 50.7%.
That's sort of why the responses in this thread that go along the lines of "The runners I know have girls..." are so comical. We are talking about small changes across large populations.
https://www.renalandurologynews.com/home/news/urology/reproductive-medicine/low-sperm-count-may-decrease-likelihood-of-siring-a-son/Why did Ed Eyestone have so many kids?
Is it what I'm thinking??? wrote:
Why did Ed Eyestone have so many kids?
I have no clue. Do you?
Does it really matter? I will say we have one of each...boys are way more of dare Devils at a younger age. I also feel like my daughter and her dad are like two peas in a pod. She listens to her dad way better than me sometimes. My son is the opposite though...
High mileage; all boys here - 5.
Zee wrote:
Does it really matter? I will say we have one of each...boys are way more of dare Devils at a younger age. I also feel like my daughter and her dad are like two peas in a pod. She listens to her dad way better than me sometimes. My son is the opposite though...
Nah, it doesn't really matter - just that it was a thread that prompted a discussion.
My boys run the gamut of cautious to dare-devil; no one the same level. But, oldest is the most daring, and youngest is the least daring....probably due to watching some dare-devil experiences by the older boys turn out badly.
They all listen to me pretty well; my wife, not so much (I think that has more to do that she is fairly long-winded and detailed, whereas I focus on keeping answers short and simple, and try to let them figure things out on their own)
It's was true with me: 4 girls and no boys.