Girls who share a womb with boys tend to make less money than those with twin sisters
Female twins who shared a womb with a brother tend to get less education, earn less money, and have fewer children than girls who shared a womb with another girl, according to an analysis of hundreds of thousands of births over more than a decade. Researchers suspect the cause is testosterone exposure during fetal development, though the exact mechanism remains a mystery.
"I think it's a really interesting look at how this really complicated system might impact females," says Talia Melber, a biological anthropologist at the University of Illinois in Urbana who wasn't involved in the study. Still, she cautions, a lot more work needs to be done to establish a causal link.
Fraternal twins, in which each of two eggs is fertilized by a different sperm cell, occur in about four of every 1000 births. About half of those result in male-female twin pairs. Typically, about 8 to 9 weeks into gestation, a male fetus begins to produce massive amounts of testosterone, which helps jump-start the development of male reproductive organs and brain architecture; female fetuses receive only modest amounts of the sex hormone. In male-female twins, though, small amounts of the male fetus's testosterone can seep into the female twin's separate amniotic sac. Scientists have known about this phenomenon for decades, and have been arguing for just as long over what effects, if any, it has on women later in life.
[...] Controlling for factors such as birth weight and maternal education, women who had a male twin were 15.2% less likely to graduate from high school, 3.9% less likely to finish college, and 11.7% less likely to be married—compared with women with a twin sister. They also had 5.8% fewer children and earned 8.6% less money, the team reports today in the Proceedings of the National Academy of Sciences.
Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins (open, DOI: 10.1073/pnas.1812786116) (DX)
(Score: 0) by Anonymous Coward on Tuesday March 19 2019, @10:48AM (1 child)
Because if it's less than 200,000 cases in the world at a given point in time then no one will care
(Score: 2) by VLM on Tuesday March 19 2019, @05:34PM
Oh, it could add up. The interesting part is the article goes to great length to only discuss prenatal exposure; yet its "widely known" that something like 50% of all trans eventually suicide, so FtoM trans seem to also colloquially also experience the overall "exposing females to unnatural levels of testosterone screws them up", not just prenatally. Or there may be no correlation for adults, perhaps mentally ill people tend to suicide in a general sense, so trans women are mentally ill leading to their demise regardless of testosterone. It could be medically useful beyond extreme levels of suicide; perhaps FtoM trans would be medically advised to aim for a more soy-boy look than a masculine look by minimizing injections if they want to graduate school or whatever.
For a guy who lifts weights I don't know enough about steroid use to comment on the sufferings of female roiders. Broscience and gym gossip seems to indicate absolutely nothing bad happens with steroid use until abusers get to levels that are ridiculously high and over the top, then the users tend to get really sick and messed up quickly in an acute sense. I don't have much data on sane levels of use, possibly because nothing bad happens to sane users. Then again at the broscience gossip level I don't think the general public could mathematically notice if female roid weight lifters experienced 3% lower college graduation rates or whatever small numbers listed.
(Score: 1, Insightful) by Anonymous Coward on Tuesday March 19 2019, @11:18AM (23 children)
Why would they conclude this is biological and not a result of the social effects of having a twin brother instead of a twin sister?
Cue "toxic masculinity" jokes.
(Score: 3, Informative) by terrab0t on Tuesday March 19 2019, @11:51AM (1 child)
They didn’t conclude that it’s biological. It’s what they suspect.
I’m sure they are considering other factors.
(Score: 1, Insightful) by Anonymous Coward on Tuesday March 19 2019, @12:02PM
Have they controlled for exposure to green jelly beans [xkcd.com]?
(Score: 0) by Anonymous Coward on Tuesday March 19 2019, @11:54AM
<sarcasm>If this chemical is so toxic then shouldn't we eliminate it?</sarcasm>
(Score: 5, Insightful) by Immerman on Tuesday March 19 2019, @01:21PM (10 children)
Agreed. Going from "the girls in mixed-gender twin pairs suffer a disadvantage" to "prenatal testosterone is the suspected cause" is a rather huge leap, especially when they don't even have a suggested mechanism for their assumption.
Given the social and evolutionary value placed on boys (males can spread their genetic material across the population much faster than females - higher risk of low fan-out, but potentially much higher reward), it would not surprise me at all to find that in having to split attention and resources between two age-synchronized children, the boy would tend to get preferential treatment.
And that's before we even get into the different biological and/or socialized behaviors expected from children of different genders - which would likely tend to bias things even more strongly in favor of a boy. Not to mention the social backlash against a girl who picks up "male" behaviors from her twin.
(Score: 2, Insightful) by Anonymous Coward on Tuesday March 19 2019, @02:10PM (2 children)
Feminine males are routinely assaulted and harassed not only by their peers but by the grownups in their life. At school, they are subject to institutional harassment and humiliation. Some of this centers around gym class, but it is pervasive.
So whatever it is that we do to masculine girls must be worse, right?
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @05:50AM (1 child)
Yes, they are.
From what I've seen, up until age 30 or so girls like the bad boys with gushing adrenaline oozing testosterone
After hitting 30 they start looking for a male who has money and or is friendly
Although by that time it's possible that those males have learned that paying for sex is cheaper and easier
(Score: 0) by Anonymous Coward on Sunday March 24 2019, @08:58PM
Chose to be V-Safe, because fuck why would I want to pass my genes on?
I'm now in my late 30s without many female successes, I've started pulling the 18 crowd with daddy issues. Unfortunately they pretty much all want you to treat them as a slut and help them get gangbanged. Which isn't really my thing. But I'm at girl 6 or so, which is making it hard to refute that at least this demographic has a stereotype (and this is a random sampling of girls from all over, white, asian and black.)
(Score: 2) by HiThere on Tuesday March 19 2019, @04:52PM (1 child)
Actually, there are reasons why that should be suspected. Look up freemartin. https://www.google.com/search?q=freemartin [google.com]
Whether this applies to humans is a decent question, and there are lots of reasons to think that one would expect such an effect from social causes. (Boys tend to be more invested in than girls by the parents.) But to suspect a biological cause is also not unreasonable.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by Immerman on Tuesday March 19 2019, @06:19PM
Freemartins are chimeras though, whose bodies contain both male and female cells, so there's a lot more than just placental hormones involved: https://en.wikipedia.org/wiki/Freemartin [wikipedia.org]
And even with freemartins I see no suggestion of any handicap that would interfere with education or earning potential.
If they were talking about *physical* symptoms, I would certainly be inclined assume a physical source - but since the symptoms appear to be social, I think assuming a physical source is grossly premature.
(Score: 4, Informative) by slinches on Tuesday March 19 2019, @05:42PM (4 children)
I scanned the study and they attempted to control for the nurture side of things by looking at the differences between twins of same and differing gender where one of the twins died soon after birth. The sample size was too low for very early deaths, but the trend held with sufficient statistical significance for those whose twin died before they were 1yr old. It's hard to tell if there might be some other confounding factors, but it does tend to point to some sort of prenatal effect.
It would be interesting to look at this in the context of single births with varying levels of testosterone in the mothers to see if there are similar differences in outcomes for girls. That could help determine whether the fetal testosterone exposure hypothesis is worth pursuing or it could point to something else.
(Score: 3, Interesting) by Azuma Hazuki on Tuesday March 19 2019, @06:33PM (2 children)
I do wonder sometimes about the effects of fetal testosterone. Specifically, I wonder if I might be a "freemartin," which itself was a slang term for lesbians for a long time, and if my mother just had higher than normal T in her bloodstream as she was carrying me. I've read gay women do have slightly masculinized brains, and I always did have an interest in science and computers and suchlike from a very young age...
I am "that girl" your mother warned you about...
(Score: 0) by Anonymous Coward on Sunday March 24 2019, @09:02PM (1 child)
nurture.
When I was a kid the tomboyish girls were mostly into guys, although out of my age range. Sadly once I reached my teens or so, the tomboyish girls all seemed to be either lesbians, bisexual domme types, or the rare straight one was married.
Having said that, there was this SUPER nerdy, SUPER HOT girl when I was in college who was such a big nerd that she reject me with the fact that I was both too young and not nerdy enough for her, because she had run an 8 line BBS from home off her after-school job before I had purchased my first 2400 baud modem.
I would have married that girl :)
(Score: 2) by Azuma Hazuki on Monday March 25 2019, @04:41AM
I was never a tomboy though. I'm still way into the femme side, though not lipstick, and if anything even nerdier than ever.
I am "that girl" your mother warned you about...
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @05:53AM
So one twin dies. Do they control for the depression in the parents?
Because I can totally see losing a kid making for a pretty dour household where the surviving kid(s) are not as engaged in play and learning.
(Score: 1, Insightful) by Anonymous Coward on Tuesday March 19 2019, @03:40PM (8 children)
Because they controlled for that. Read the paper.
If you just read headline, articles and even paper titles you're not going to understand what a given paper is about. Media goes through published papers looking for anything that can spice up their science section. They'll take any excuse to write a story on something they can play off as interesting. You need to read the abstract at a minimum to get any idea of what the paper is really about, and usually the detailed methodology (i.e. the meat of the paper) has a huge impact on the meaning of the result.
If you find yourself asking "why did they conclude X?" that's _exactly_ what is in the paper. Half the time you'll find X didn't even mean what you initially thought it did.
(Score: 2) by kazzie on Tuesday March 19 2019, @05:14PM (5 children)
Did they, though?
I've had a brief read of the paper, and I can't find anything to say that they controlled for the social influence of having a twin brother (instead of sister):
Controlling for the mother's age and education catches the social influences of the family as a whole, but it doesn't address the newly arrived sibling.
Example hypothesis: Because there is a societal bias toward encouraging more males into high-paid jobs than females, a female with a male twin will see this attention and encouragement focused on their brother as they grow up. If both twins are female, then the attention and encouragement will be more equally divided between them, resulting in higher average earnings.
It might be interested to compare their results with a third group, namely pairs of male fraternal twins.
(Score: 3, Informative) by FatPhil on Wednesday March 20 2019, @11:50PM (4 children)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by kazzie on Thursday March 21 2019, @10:24AM (3 children)
Right, I missed that. That'd add weight to their hypothesis.
(Score: 2) by FatPhil on Thursday March 21 2019, @11:22AM (2 children)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by kazzie on Thursday March 21 2019, @05:26PM (1 child)
I suspect a lot of that would be caught by controlling for the mother's years in education.
(Score: 3, Touché) by FatPhil on Thursday March 21 2019, @08:53PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by Osamabobama on Tuesday March 19 2019, @06:02PM (1 child)
I see you are leading with your strongest material.
Okay, that's amusing, but you should have used it as a build-up to the punchline that you delivered at the beginning. I'm not sure you understand your own comedy.
There is longstanding tradition on this site and those like it not to read the articles (let alone academic papers!). There will generally be a few people, though, who do read it and explain how the clickbait headline has it all wrong, or whatever. I guess you're not the person for that role, but few of us are. Just try to keep the overall dynamic of social news in mind to avoid future etiquette breaches. Thanks.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by FatPhil on Wednesday March 20 2019, @11:58PM
https://www.pnas.org/content/pnas/early/2019/03/14/1812786116/F1.medium.gif
Look at the error bars. A claim of A > B where A's error bar descends lower than B's error bar is, erm, not hugely convincing.
If you read more, you might notice phrases like "on the margins of significance".
In science-speak, that means "not significant" with a /soto voce/ "shit we didn't get the result our confirmation bias promised us" (read the first sentence - they were definitely striving to confirm the conclusion).
Also note that this was multivariate regression, which is a fancy way of trying to get away with p-hacking - if you throw enough parameters in there, some will correlate with each other.
It looks like they did put in enough leg-work, it was a big study. But if the effect was so insignificant, then this is simply not an issue worth wasting any time/money/effort over.
So there's no point banning green jelly beans because of this.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by terrab0t on Tuesday March 19 2019, @11:55AM (32 children)
It doesn’t mention any effects on males with female twin. I wonder if there are any?
(Score: -1, Troll) by Anonymous Coward on Tuesday March 19 2019, @12:13PM (2 children)
Yes, explains Aunt Nora, but not Uncle Billy. I always wonder what if both twins were half of a quadruplet, and each of that was only half of Octo-mom's spawn. Or why people thing that such things determine destiny. Khallow, for example, was a, . . . actually, I have no idea of khallow's neo-natal situation, and no interest in finding out, but the dude did just end up not being right in the head. Hormones? Or Homoeophones? Of course, the mere idea that a radical rabid libertariantard Vienna Circle economic conservative could have siblings . . . just not possible, unless contractually agreed to prior to mutual, or more properly, sequential, fertilization. Oh, my, Daddy! What if there are different genetic fathers? Oh, crap, khallow, I got tested, and in a reverse Darth Cheney move, I am NOT your Father, khallow!! I'll still will cut off your hand, though, just to see what you do without the Obamacare to get it replaced! Ha! Sucks even to be a Jedi, if it does not come with single-payer health benefits!
(Score: 1) by khallow on Tuesday March 19 2019, @12:21PM (1 child)
Sorry, I've been postnatal for decades and can no longer provide the hormone balance you need in your amniotic sac to appear normal human. But please tell us how your birth goes or better yet YouTube it. We love to hear/view those disaster stories!
(Score: 0) by Anonymous Coward on Tuesday March 19 2019, @01:44PM
It's more environmental sustainable if you just look into the mirror.
(Score: 5, Insightful) by The Mighty Buzzard on Tuesday March 19 2019, @12:16PM (26 children)
Nobody's interested in males anymore. Researching the males wouldn't get them any social justice dollars or cred unless they were able to say we're horrible and should be ashamed.
My rights don't end where your fear begins.
(Score: 4, Insightful) by Runaway1956 on Tuesday March 19 2019, @02:01PM (2 children)
We should just enjoy being toxic masculines. Life does have it's rewards.
“I have become friends with many school shooters” - Tampon Tim Walz
(Score: 2) by The Mighty Buzzard on Tuesday March 19 2019, @02:13PM (1 child)
"Nothing can defeat the penis!" -- Alexander Lavelle Harris
My rights don't end where your fear begins.
(Score: 2) by FatPhil on Thursday March 21 2019, @12:00AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 4, Insightful) by Azuma Hazuki on Tuesday March 19 2019, @06:36PM (22 children)
Oh yes, men are *so* persecuted in this country. But don't worry; justice will take its course. Someday, sometime, we may even have a man as President.
...or, you know, FORTY FIVE OF THEM IN A ROW. Christ, you're worthless. If things are starting to suck for you as a man, step back and look at who is making your life suck. Hint: it's almost entirely other men. Always has been. This is why men need feminism.
I am "that girl" your mother warned you about...
(Score: 2, Funny) by Anonymous Coward on Tuesday March 19 2019, @06:49PM (2 children)
Oh dear, there she goes again. :-(
(Score: 0, Funny) by Anonymous Coward on Tuesday March 19 2019, @07:11PM
Or more likely triggered males are narcissistic whiny man children. Sucks when someone blows your cover huh?
(Score: 2) by The Mighty Buzzard on Tuesday March 19 2019, @11:58PM
I know, right? Some folks just got no sense of humor.
My rights don't end where your fear begins.
(Score: 2, Informative) by Anonymous Coward on Tuesday March 19 2019, @07:36PM (11 children)
Your counterexample is not valid because we are talking about a pretty recent phenomenon: white host in the past several yrs, but got started in the 1970s. The past several years have been bizarre in their male attacks. As a lesbian, you presumably don't live with a man or have male children so you are not truly aware of the extent. The Left has gone crazy on this topic.
(Score: 0) by Anonymous Coward on Tuesday March 19 2019, @07:46PM
Correction: "white hot"
Damn autocorrect.
(Score: 2) by Azuma Hazuki on Wednesday March 20 2019, @05:21AM (9 children)
And yet like any woman, I am surrounded by men and the world men have made everywhere I go. I see men suffering terrible things...done to them almost entirely by other men. This is one reason I keep saying men need feminism and feminism needs men: because the excesses and cruelties of "the patriarchy" are inflicted on innocent men to begin with, and most of you are told "well at least you're not a woman" as a redirection.
Who starts wars? Men, leaving aside a few weird edge cases like Boudicca. Who is it that has a problem with gays? For the most part, men, and that means gay or just effeminate men suffer horribly at the hands of men for being who and what they are...because they are associated with women and being woman-like. Who is driving this continued, ever-worsening boom and bust cycle? Pretty much all men, though I hold every single female CEO just as complicit (Liz Holmes, I'm lookin' at you...). Who does most of the human trafficking? Again, almost all men, and yes, there are some male victims of it despite it being almost a textbook example of male sexual violence against women. Whose bodies are used to advertise fucking everything, and usually in the most exploitative, objectifying ways possible, and by whom? Womens', by men. Why can't men get help when they are victims of domestic abuse? Because *other men* tell them "that doesn't happen to men," in effect.
And you've fallen for it hook line and sinker. You suffer all this, and see others suffer it, and willingly allow it to continue because at least you can dump on women, at least you're not a woman, at least you have that Y chromosome going for you. Guess what? SO DO THE PEOPLE WHO ARE MAKING YOUR LIFE HELL. You have more in common with me than you do a rich man. Think about that.
I am "that girl" your mother warned you about...
(Score: 1, Insightful) by Anonymous Coward on Wednesday March 20 2019, @06:12AM (1 child)
Prostitution rings are frequently managed by "madams". Recall old Heidi Fleiss, Madam to the Stars.
What you are blinded to is that you see men as the agents of evil rather than what is really happening: people who have the means to do so indulging themselves.
Put women in positions of power and many of them will be insufferable cruel bitches (Leona Helmsley--an ancient example). The human trafficking stories I am most aware of are household servants who are slaves beaten and humilated by a Chinese, Arab, or Indian she-devil matron. Power corrupts and it pays no heed to sex.
(Score: 2) by Azuma Hazuki on Wednesday March 20 2019, @06:33AM
You think I don't know this? I don't think a woman is automatically angelic or innocent just by virtue of being female, and those "madams" are some of the lowest of the low. And forget Leona Helmsley, what about Irma Grese? If it comes to that, the person who's hurt me most in my entire life was another woman.
None of that negates my other points. God damn it, man, I'm *defending* the vast majority of men, proclaiming them to be largely innocent of the worst of male abuses, and you jump all over this like I proposed eliminating half the human race and blasting off into space a la Vandread to create a lesbian-separatist Dyson sphere or something.
I am "that girl" your mother warned you about...
(Score: 4, Insightful) by deimtee on Wednesday March 20 2019, @06:12AM (4 children)
And this is an example of the core dissonance between yours and TMB/Runny/KHall/etc, viewpoints.
You blame "Men" as a whole when the truth is that it is the 0.1% who start wars, and always was.
You claim that "Men" have had 45 USA presidents in a row. True, but it is more accurate (smaller grouping) to say that the 0.1% upper class have had 45 presidents in a row.
You blame "Men" as a group for discrimination, while simultaneously claiming that blaming any other group for the individual actions of its members is wrong.
200 million years is actually quite a long time.
(Score: 3, Interesting) by Azuma Hazuki on Wednesday March 20 2019, @06:27AM (3 children)
You misread me here: I am not saying "all men and every man are directly responsible for $EVIL_THING." I am saying that within the set of "humans responsible for $EVIL_THING," the vast majority of them are men, and many of their victims are male as well. Read for comprehension, *please.*
I am "that girl" your mother warned you about...
(Score: 2) by deimtee on Wednesday March 20 2019, @09:22AM (2 children)
Yet in almost every case you refer to them as men. Not 'the sexists', or 'the racists', or 'the patriarchy', or 'the upper class', or 'the 1%' or even 'evil sociopathic bastards'.
The group 'men' includes many people who are not responsible for the problems, but by using by the group name you include them.
Some Mexicans are drug dealers. Is it acceptable to say 'all Mexicans are drug dealers'?
Some African-americans are violent muggers. Is it acceptable to say 'all African-americans are violent criminals'?
Some men are sexist, racist pigs. Is it acceptable to say 'all men are sexist, racist pigs'?
I think the first part is overly simplistic, but I agree with the bit I italicized. But you are contributing to the very problem you are complaining about by then referring to them as 'men' every time you have a problem with someone's behaviour.
200 million years is actually quite a long time.
(Score: 3, Interesting) by Azuma Hazuki on Wednesday March 20 2019, @09:56AM (1 child)
This must be that "fragile masculinity" I keep hearing about so often recently...
Try it like this: "in the set of [people who do $BAD_STUFF], it is observed that most of the members of the set are men." Does that help any? I'm not backing off this, because I'm not wrong.
I am "that girl" your mother warned you about...
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @06:40PM
My wife made me do it.
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @06:22AM (1 child)
One of your examples needs to be mentioned: "human trafficking."
For the most part, this is just a new marketing term for prostitution, something that is legal and regulated in many Western countries.
As far as prostitution, there are different strata of prostitute. The bottom ones are quite bad and may involve coercion or drug addiction. These are the street walkers. At the top you have the call girl who is pretty safe, doesn't work many hours, and makes a lot of money. She goes into it of her own volition and it is a rational job choice, although one should recognize like an actor or athlete it is based on physical appeal and therefore usually has a limited span as a "career."
I hope you weren't conflating *all* prostitution with a slavery ring.
(Score: 2) by Azuma Hazuki on Wednesday March 20 2019, @06:37AM
If I'd meant all prostitution I'd have *said* all prostitution. As it is, I do think someone should be able to go and do "camgirl" (or "cam-boy" for that matter) work if s/he wants to, but that's about it. There's too much danger to the person being prostituted otherwise, even in cases of supposedly independent free agents working for themselves: disease, kidnapping, robbery, injury, death, health issues, the list goes on.
I am "that girl" your mother warned you about...
(Score: 2) by The Mighty Buzzard on Wednesday March 20 2019, @12:05AM (4 children)
That was humor in the form of exaggerated despair. It's not something I'm actually worried about. The snowflakes who get so horribly triggered by masculinity even existing are almost entirely pampered women and beta males, both of which are utterly pathetic in conflicts of any sort.
My rights don't end where your fear begins.
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @06:15AM (3 children)
The pampered women may hang out with the beta males crying about toxic masculinity, but they go out and pick up a 'bad boy' when they feel like a good fuck.
(Score: 2) by The Mighty Buzzard on Wednesday March 20 2019, @10:30AM (2 children)
Some sort of alpha anyway, yep. Unless they prefer to eat at the Y.
My rights don't end where your fear begins.
(Score: 2) by FatPhil on Thursday March 21 2019, @12:09AM (1 child)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by The Mighty Buzzard on Thursday March 21 2019, @03:45AM
Mea culpa.
My rights don't end where your fear begins.
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @06:37PM
Well there you have an excellent example of estrogen.
I wonder if this study was done on white male testosterone? That's the most toxic testosterone after all.
(Score: 0) by Anonymous Coward on Wednesday March 20 2019, @06:59PM
Yes I know, but I'm not even sure those who do it can see it themselves. It must some kind of systemic thing of the matriarchy.
I always thought women were to smart to become president and men did it to impress women.
(Score: 2) by slinches on Tuesday March 19 2019, @06:09PM
They did address this question by noting that there is a more noticeable impact on the characteristics of females in mixed animal litters, but that isn't a very satisfying answer. Even if they didn't expect a difference in male twin outcomes, they would have had the data at hand and the cost of looking at it would have been trivial.
(Score: 3, Insightful) by Immerman on Tuesday March 19 2019, @06:24PM
Any effects (biological at least, which the study is assuming largely without evidence) would likely be far smaller - primarily because a male fetus is already being subjected to most of the full range of hormones in its mother's body, so any increase from a female twin is unlikely to substantially alter the ambient environment.
(Score: 0) by Anonymous Coward on Tuesday March 19 2019, @06:48PM (1 child)
How do girls with a twin brother compare to girls with a brother a year apart in age? Same with twin sisters compared to sisters a year apart.
Without that done, any conclusions from the study not worth the bytes they are written with.
(Score: 2) by FatPhil on Thursday March 21 2019, @12:11AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves