Not quite, since you could also have bastards who never suspect it. It’s possible that whether someone suspects they’re a bastard is completely unrelated to whether they actually are one, in which case the general-population figure would be the same as for the suspect cases.
You’d think, though, that you could get a good estimate for the general population from studying just how well Y chromosomes actually correlate with surnames. If everyone conformed to the nominal case (biological father is husband of biological mother, with entire family taking father’s surname), the correlation would be exact. Of course, you’d have to account for the “legitimate” exceptions (family not taking father’s name, adoptions, etc.), but those are probably a lot easier to study, since folks probably aren’t lying about them. And you wouldn’t be able to detect women cheating with their husband’s brother (or other close relative, though those are probably rare), but no method is perfect.
As already said, no. In fact, I get really annoyed when older books (before blood types and therefore paternity test were about) use the “s/he looks like a spitting image of X, so they must be an illegal or swapped at birth child” clichee, because from looking around at me, most people don’t resemble their parents strong enough to be spitting images.
And personality traits are not only all over the map, but also influenced much more by nurture than looks. Even if we talk about extreme things like psychological illnesses, remember that genetics and heritage in most cases is not 100%. Even in clear-cut Mendel cases of single-allel and dominant-recessive traits - which are a very small part of traits* - Mendel’s law state that the F1 would look different from the parents, and only the F2 would show some Parent traits.
The typical examples given in High school text books for directly inherited traits are:
blood type O (because it’s recessive, the others can be mixed)
blue eyes (again because they’re recessive, so two blue-eye parents can’t have a brown-eye kid)
tongue-rolling (can you roll your tongue at the edges lengthwise or not? It’s inherited)
Ear lobes - are they attached or not?
That’s it. All other factors are not easily visible or not directly obviously inherited.
Actually, the cite I’ve heard most often is 10% - after a lot of data from blood type and DNA studies came in, researchers concluded that on average, - in every society! - about 10% of children were cuckoos. (Given that not every fling ends in pregnancy, this means even more cheating goes on).
Sure there is some extrapolation to remote small tribes, but it’s a combination between psychologists, sociologists and biologists / medical doctors confirming that it’s human nature to cheat (and until very recently, to occasionally get pregnant from it), despite different social attempts to stop this with punishment/ social outcasting.
Actually comparing Y-chromosome to surnames would not be very helpful because you would need to establish a family tree first; and if you back a few generations, people married cousins and other relatives, confusing the family tree. Beyond several generations, data is too sparse to be of value.
The other question is why this matters? If you have a child in your home and raise them, it’s your child. Why does biology matter? The only reason I can see is when the child has a medical issue and needs a donation (bone marrow, kidney, etc.) from a close relative, and suddenly it turns out that dad is not blood related.
But being blood-related is no guarantee for matching, either, because a bio-Dad only contributes 50% of DNA. There are enough cases of children needing bone marrow etc., who get it from their siblings or uncles or farther removed relatives who turn out to be a better match.
And the whole idea behind the (working) bone marrow registry is that because genetics play funny during recombination, two complete strangers can be a close enough match.
Not according to my friend who was doing research on the genetics of Huntington’s disease, where the people involved were not suspicious of paternity - they were just looking at family relationships trying to track down what genes might be involved. I don’t remember the exact number she quoted me, but I remember being somewhat shocked by how high it was. (I’m pretty sure it was at least 5%, but I don’t remember what it was.) It’s definitely high enough that genetic researchers have to do “paternity” testing on their “family” specimens to make sure that they’re looking at actual genetic relationships in evaluating their results.
My Mother is of African descent, and has dark-olive skin, brown eyes and thick wiry brown hair. Both of her chidlren have blue eyes and blonde hair. My Brother’s skin is fair but tans easily, mine is fair and goes white/red/white when exposed to the sun.
I’ve heard that there’s some variation in the number depending on socio-economic class. That there’s a correlation between level of education/income and lower rate of cuckolding. The number I heard (without support) was about a 3% rate at the well educated, middle class level.
Not sure if that’s true, but it’s certainly plausible. You also tend to see an older age for first marriage with rising income or education and more acceptance of contraceptives, so it’s certainly plausible there would also be a lower rate of cuckoos. Of course, this would also imply there’s a higher than 10% rate (maybe even approaching that 25% number) at lower levels of income or education.
Not for nothing, an old girlfriend from high school found me on Facebook, and I was looking through some of her pictures when I discovered that her son looked almost EXACTLY like me. Same nose, same ears, cowlick in his hair in the same direction and same spot as mine. :eek:
She swore up and down that he wasn’t mine, and I have no reason to doubt her. I can only assume that his father looks like me, or that the boy (er, young man, as he’s pushing 20 now) has a father who looks nothing like him.
My wife is Asian and I’m white. The first time we took our newborn daughter to the pediatrician she looked at our daughter, then my wife, then me, then back at my daughter. Finally she said, “That’s a real interesting combination of the two of you there.” FWIW, I always thought my daughter looked more like my mother than anyone else in her family tree.
IIRC something like 1/5th or 1/3rd was what the military discovered when they collected blood type data when they first started experimenting with blood transfusions.
Really it makes sense; it’s men who have the reputation for cheating in our culture, but who do you think they are cheating with? Not each other. Although I wouldn’t be surprised if the number of “cuckoos” has fallen significantly though, since fewer people are being pressured into unwanted marriages (women who actually like their husband are no doubt less likely to cheat) and having mixed families.
A whole lot of what makes kids look like their parents is learned behavior, albeit subconscious. Facial expressions, gestures, even the way they walk. I watched my son take on many of the characteristics of my (now ex) husband, who he was not genetically related to. People would often comment on how much he looked like his “dad”, and they weren’t wrong - he did, but it wasn’t because of a genetic link.
And, of course, denial is a strong force. People who may suspect they’ve been cuckolded will often go to great (again, subconscious) lengths to convince themselves that the kid “is the spitting image” of themselves, and family members often reinforce that.
Finally, there are just so many eye, chin and nose shapes in the world, and it’s not hard to find someone who resembles you even if you know they’re not related. My daughter has my grandmother’s nose, no doubt about it. And yet when my ex-MIL showed me a baby picture of my daughter, I thought, “huh, when did that get taken?” until she moved her hand and my “daughter” had a penis! It turned out to be my ex, my daughter’s father, as an infant. She really does have the same nose he had as a baby - or rather, he and my grandmother and my daughter all have very similar noses, although they’re not all related to each other. So does my daughter have my grandmother’s nose from me or her father’s nose from him? Depends on which side of the family you ask!
Yes, high school text books did and do say this, but eye color is controlled by multiple genes and it’s perfectly possible for two blue-eyed parents to have a brown-eyed child. All that’s necessary is for Parent 1 to lack the gene for the X step in producing the pigment while Parent 2 lacks the gene for the Y step.
It’s common for 2 blue-eyed parents to have only blue-eyed children, but it’s not absolute.
Reminds me of when I worked in HS…with some guys in their 20’s loading trucks at night. For some reason they asked me what I was studying at school and I said ‘genetics’. They started asking many questions about it.
Well, I chose an example but cannot remember what it was. Turns out that one of the guys working there had my example. His kid had x which was a ?recessive? trait. His wife did not have that trait but many in her family did. He did not have that trait and noone in his family did.
He started asking more and more questions and many ‘what-if’s’. Finally I looked at him and said…it’s HIGH SCHOOL genetics and you are talking with someone just learning it. In addition, recessive traits are sneaky…they can be present in you even though no-one in your family has it.
He went home that night and confronted his wife. His wife confessed the kid wasn’t his. Divorce followed.
The guy THANKED me for talking to him about it…I didn’t know whether to feel like shit or whether good had resulted.
Since a lot of people tend to date within the same ethnic group & phenotype, & women may in fact have a “type” that includes both lovers, it can be pretty vague.
Also, some observers are pretty bad at noticing subtle similarities as opposed to flashy elements like red hair or an aquiline nose. So it may just be below the threshold of noticeable difference some of the time.
And there’s a bias from known information. Rarely do people say I look like my bio-dad, because they don’t know he’s my bio-dad. People have spontaneously mistaken me for one of my mother’s brothers, because I used to spend a lot of time in circles where my mother’s family is well-known.
This happened to a friend of mine. The oldest daughter looks nothing like him. Her personality vastly different. The younger daughter is a carbon copy of him.
With the eldest, at first he wasn’t sure. Maybe she looked like someone on her family side. People told him all the time she looked like him… Even his own mother. Still the nagging thought never went away. Then it became believing because of the ramifications of what might happen if she wasn’t his. In time the nagging was so unbearable that he tested. She’s not his biologically.
The relationship with his wife is in ruins. He is in a country where divorce is still frowned on. He’s afraid if he divorces she’ll take the children, etc.
He’s in turmoil as to if he should tell his daughter one day.
The article linked (to the photo of the norwegian footballer??) I thought the daughter looks more like the mother than the father. Then, according to the translation, that’s not her mother. Who knows, maybe all nordic types look alike…
My uncle looked like nobody else in the family. My dad said he and the other uncle used to call him “changeling” growing up. My grandmother’s reaction to seeing my brother for the first time in 15 years was how much he looked like that uncle. (He does) So it’s not that my grandmother was fooling around in that case… Traits skip generations…
Sometimes cheeks, chin, nose, eyes - it’s obvious. Sometimes two siblings look very different. One article I read on parental discrepancies said that occasionally, in a case where for example they were looking for donor matches in a family, a mother would pull the doctor aside and ask them not to say anything about very mismatched genetics. They know.
I agree, I find it hard to believe the number is as high as 10% or even 5%, especially today where birth control is available, divorce is easy, and (as mentioned above) shotgun marriages are rarer.
There is the often-mentioned story about a British lower class neighbourhood where the teacher assigned homework on blood types, only to find that 20% of the children’s blood types did not match parents. First, I have never found a reference to the actual story itself online (it’s apocryphal, I’m sure, like Marco Polo and spaghetti). Secondly, how many lower class couples or kids in England 30 or 40 years ago knew their blood type?
Blood typing has been around quite awhile. As a WAG, a lot of folks in the WWII generation may have gotten typed either while being treated for injuries or as part of a blood donor program. Actually, donating blood is still a good way to get blood typed. So it doesn’t surprise me that “lower class” people 30 or 40 years ago might know their blood type.
I think in some cases, particularly involving eldest children, the child might have been conceived prior to marriage, or even born prior to marriage, and the father married the mother knowing the eldest would be a step-child - probably not very common, but such circumstances did happen (and still do). In some cases, it might have been a situation where a married couple adopts an out-of-wedlock infant to hide the out-of-wedlock pregnancy - probably still happens. For example, Jack Nicholson’s “mother” was really his grandmother, and his “sister” was really his mother - so his “father” wouldn’t have been his father at all, but that would have been known to all parties involved except him (he eventually found out, long after he was adult). It used to be common for adopted infants not to be told about their adoptions. There might have been a sperm donor involved due to male infertility - usual practice is to try to find a donor of similar appearance to minimize awkward questions, and it used to be standard practice to tell no one about the sperm donation. There is also the phenomena known chimerism, where a parent has two genomes, meaning they might pass on a blood type to a child they don’t have themselves. Alright, that sounds confusing. Here, read this Wiki on Lydia Fairchild, who was accused of stealing someone else’s kids because of the genetics involved. Some of the cases of “infidelity” might well be chimeras, either the mother or the father. No one knows how common chimerism is in humans, it’s called extremely rare because no one has gone looking for it before and thus we only know about the cases we stumble upon. Who knows how many instances are simply never detected?
Bottom line, it isn’t always about infidelity. There may be deception in the case of hiding socially unapproved birth circumstances, but one shouldn’t assume, upon discovery of such questionable paternity, that there was cheating going on. Wisest just to keep one’s mouth shut in such circumstances.
It appears that the presence of oral contraceptives add another variable to the equation. From a couple studies mentioned in this Scientific American article: “Going on or off the pill during a relationship, therefore, may tempt a woman away from her man.” It seems that women on the pill tend to prefer men with similar major histocompatibility complex (MHC) genes, but while her ovaries are operating on autopilot, she leans towards her opposite type.
We tested our own blood in a high school science class; I showed AB. My Dad’s dogtags from WWII show Type O. For many years I assumed I’d fouled the high school experiment; I eventually retested: again, AB. Yet, I know my Mother; and I know how much I resemble my Father, not just physically but psychologically.
We can’t test him, but I guess it would be easy to arrange to test my much-younger sibling and I to determine if we share one parent or two.
I’d bet a substantial sum that we’d “pass” the test; that my Dad’s Navy blood test was faulty.
