Slashdot Mirror
Engineers Have More Sons, Nurses More Daughters
Bifurcati writes "While it might be irrelevant for many /.ers, a recent study has shown that people in stereotypically male professions (engineering, IT, mathematics, etc) are more likely to have sons than daughters, while nurses, therapists and teachers tend to produce more girls. Based on independent survey data, engineering types produce 140 boys to every 100 girls, while nurses and the like produce 135 girls to 100 boys. The explanation is unclear, but it might have interesting long-term social implications. A more detailed summary of the journal article is available on Illuminating Science."
More testosterone in the womb leads to boys.
What does this have to do with the father? What does this have to do with which sperm gets into the egg?
Transcend Humanity. Please.
The article doesn't mention cause - it's an article about the correlation, and nothing more.
Video Phone Blogs send video messages straight to the web.
Interestingly, my team (about 20) is almost the exact opposite. On our unix admin team (maybe a dozen) we have a guy with 1 daughter, another with 2, another with 1, another with 3, etc. Interestingly, our female members have boys.
What about those couples, like myself, who have an IT guy and a nurse (to be)?
-- Who is the bigger fool? The fool or the fool who follows him? --
Couples desperate to produce a son could boost their chances if one or both of them switches to a "masculine" profession such as engineering or accountancy, a report has said.
The gender is determined by the chromosome set when sperm and egg fusion. That has nothing to do with testosterone levels later experienced in the womb.
Of course, the media has promptly taken things one step further and suggested that "Couples desperate to produce a son could boost their chances if one or both of them switches to a "masculine" profession such as engineering or accountancy". Perhaps this is true - but that might be reading more into the report than is good for it.
Realities just a bunch of bits.
This is interesting. It is well established that diet does contribute to fertility. The average age of menarche in 1900 was 15 and now it is 11. This is because of improvement in diet which means woman have a higher chance of conceiving much earlier as they can support a pregnancy. Women have XX chromosomes and Men have XY chromosomes. Each contribute one of those sex chromosomes to their child to give a specific sex: M/F. If there is a dietery link/psychological(environmental factor) link that would imply that male engineers produce more Y sperm cells that are viable than X. Secondly that would mean that the ova of nurses are less hostile to X sperms. Such a sex determining mechanism occuring at the level of gamete fusion is extremely complex. I am very sceptical that there is an environmental factor associated with sex determination in humans, at least not one associated with profession.
The parent was joking (and I'm surprised that so few have caught it), but apart from that, gender is not simply tied to chromosomes. In fact, there's only one small section of the Y chromosome that causes virilization (SRY) (of it, only one or two genes start the process), and this has been known to migrate on occasion to other genes. There have been a number gender-affecting of mutations that have occurred in the region (including, in one case that I read, a two BP mutation that caused a normal XY female. In another case, a normal XX man didn't even have a migrated SRY, but simply had virilized from other, unknown effects.
Environmental factors can play a strong role, and might have been involved in the latter case. Excessive androgens produced by the mother can lead to degrees of virilization of the fetus; other factors may help cause androgen insensitivity and thus feminization. Gender isn't so clear cut; it just tends to migrate to one extreme or the other because that's genetically advantageous, and the Y chromosome usually acts as a carrier for the genes that activate virilization.
As for what's causing the "engineer shift", that's a really good question... that's a pretty darn big correlation that the article described.
I believe Bird-Person can arrange that.
And the Internet as a whole is a terrific place for posting as fact misreadings of misinterpretations of things people don't say. (No, not you.)
The original paper, which was a study based on a few thousand people, was looking at extreme male-brainedness in autism. They picked out profession as an indicator of male-brainedness. The data for sex of the offspring was available only one year (1994) of the data they had.
They also selected the professions ad hoc. That is, they didn't test the wider profession for male-brainedness. They didn't directly test the individual people involved either, but just looked at their profession, race, and other data.
The question is: how many of the engineer types would have had more male children anyway? Are people who will naturally have more male children just more likely to choose engineering professions? I think you could draw that conclusion more easily, but still it's only one study using data from one year out of several they studied.
sigs, as if you care.
That looks like a conclusion to me. Or were you talking about the scientifical paper itself?
"I think it would be a good idea!"
Gandhi, about Internet Security
not true. check out the solution to this: http://www.techinterview.org/Puzzles/fog0000000026 .html
I thought all cloning species are small and fast-reproducing so they can filter out bad genes that way. Where did you learn about those lizards?
Don't recall exactly - I've seen it several places (including Animal Planet).
But a web search on "lizard virgin birth" quickly turned up a bunch.
It's the Whiptail Lizard. There are about 15 species of it that reproduce exclusively by parthenogenesis - the largest vertibrates to do so.
Apparently hybridization of two other lizard species sometimes results in a female offspring that can only reproduce that way, creating a new species. The hybrid vigor then lets the population establish, making up (at least in the geological short-term) for the lack of genetic mixing. (Downsides are lack of evolution and an entire population that has nearly identical immune response - probably leading eventually to extinction from some disease that would only wipe out part of a sexual species.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Dr. Kanazawa sent me an email that stated the control variables accounted for 18.48 of the variance for boys and 15.24% of the variance for the girls. This leaves occupation of parent accounting for approximately 1% of the variance in either of the two models, suggesting to me that not much can be made from the project. I was also informed that only one parent's occupation was known for the study, so I am not sure if the children may have been counted twice or not.
Note that this adds credance to the claim that men are useless (biologically speaking). Why Is Sex Fun? by Jared Diamond touches on this a bit.
Software sucks. Open Source sucks less.
There are fish that do this, and many do require the male of another species to "fertilize" the other eggs, even though no actual hybridization goes on. I believe there are hormonal triggers that are the relic of when the fish wasn't parthenogenic.
However, these subspecies of fish generally do not last very long. Parthenogenesis is a good short term strategy as it allows higher rates of reproduction than sex. However, once you get into an evolutionary timescale these parthenogenic fish are not well equipped to adapt to changes in the environment.
These clonal colonies of fish often spring up and die out in a relatively short period of time, often times taking out the original population that they were derived from, as their higher rate of reproduction allows them to compete so well that they drive the other to extinction (at least locally, such as in a given pond) In the case where they need the males to "fertilize" the eggs, this in itself is enough to prevent reproduction and cause eventual extinction.
But then again there are many types of fish which can change gender, either almost at will (at least seasonally) or are always born one gender and then change when there is a need for the other (probably all born female, then males formed as needed.) In these case there really isn't a genetic factor in sexuality, it is simply a hormonal process.
I'll never make that mistake again, reading the experts' opinions. - Feynman
1000 families. 50% chance of GIRL
500 have a girl and stop ---> 500 girls
250 have a boy + a girl and stop ---> +250 g, + 250 b
125 have 2 boys + a girl and stop ---> +125 g, +250 b
62.5 have 3 boys + a girl and stop ---> + 63.5 g + 187 b
etc
N_{boys} = N \sum_{k=1}^\infty (k-1)*2^{-k} = N (for a population of N families, with N\rightarrow \infty, precisely N boys will be born)
N_{girls} = N \sum_{k=1}^\infty (1)*2^{-k} = N (again the same number!)
So, in conclusion, for a large sample, you will end up with each family (on average) having 1 boy and one girl...