I’ve known a handful of twin girls/women in my time, and they all seem to believe the idea that twins skip a generation. Which is to say, if Stella were born a twin, Stella’s granddaughters would be statistically more likely to be born twins (IOW, Stella’s daughter would give birth to twins).
Does biological scholarship support this idea, or is this one of those fun things that people like to believe but that has no basis in fact?
Myth.
Twins can only “run” in a maternal line, since the only genetic predisposition to having twins would be how a woman ovulates…I think.
<–Mother who was once worried about the very same thing since her child’s grandmother is a twin!
Identical twins come from a single egg.
I’ve often wondered about this, as my mother was very nervous because her family was “due” for some more twins. (Well, I suppose I could have been a twin very early and absorbed my sibling, right? Because that’s kinder than the kind of murder I would have dealt once born.)
This is almost certainly true, assuming that there’s some genetic component to having twins (which seems very likely).
But, the real question in asking whether twins skip a generation is not whether Stella’s granddaughters are more likely (than the population average) to be born twins, it’s whether they’re more likely than Stella’s own children to be born twins.
That seems significantly more farfetched, although I can’t say I have any data either way besides my basic understanding of genetics.
There’s no genetic tendency to have identical twins, either - they appear at a pretty consistent rate among all populations. To the degree that twins run in families, it’s the tendency to have fraternal twins.
But since there’s no twin “gene”, wouldn’t the possibility of twins correlate to hyper ovulation? I’m not talking about IVF babies here. And if that’s somewhat genetic, then doesn’t it makes sense that having twins is a female trait?
Bob and Jane have twins named Sarah and Lizzie.
Sarah married Sam and they have a daughter, Cecilia.
**Ceci **has twin boys, Isaac and Robert.
Robert marries Abigail and they have a daughter, Rose.
**Rose **marries Edward and they have twins.
My son’s father’s mother is a twin, but that has no bearing on my son’s likelihood of having a twin unless I had some genetic predisposition to it.
Sure - the tendency to have fraternal twins totally runs in families via the maternal line, and I’ve always assumed that this was actually a tendency to ovulate more than egg at a time. All I was saying is that identical twins don’t run in families at all.
Lots of traits are said to skip a generation, mostly due to the fact that most people don’t really understand genetics. If a parent has a trait and a child has a trait, people will say “Oh, that trait runs in families”, and assume that it always works that way. If a parent has a trait and the child doesn’t, but the grandchild does, then folks will say “Oh, that trait skips a generation”, and again, assume that it always works that way. But it’s not that it always works that way; it’s just (if anything) that a tendency towards that trait runs in families, and sometimes it shows up and sometimes it doesn’t.
And even assuming that the tendency towards hyperovulation does run in families, it need not run exclusively in the female line. A man could carry the appropriate genes, too, even though he’s obviously not going to express them himself. So you could have, for instance, a man whose daughters are all more likely to have twins.
I shouldn’t have said maternal line.
I did mean a female trait. Like the example I posted above.
As a triplet myself, I was always very concerned about having twins. During my current pregnancy, it was a great relief when we found out that there is only one.
When I expressed my concern, people would often respond with, “Oh, you don’t have to worry. That skips generations.” I wish it did…
My thought on the skipping generation idea is a guess. Suppose Sarah has twins sons, one of them Charles. Charles’ children would not be more likely to be twins because he is male and not a part of that equation. But, if Charles had a daughter, he may have passed his mothers genetic hyper-ovulation onto her, so she might be more likely to have twins then most. This might explain the “skipping a generation” idea. I am not sure if hyper-ovulation is sex-linked or not, so this is pure speculation. Maybe someone can shed some more light on it.
This would pretty much have to be the explanation considering that fraternal twins come from two seperate eggs. I wonder, though: do any women always ovulate multiple eggs? (how would something like that even be studied? ultrasound, some sort of blood test? or is it not even possible to know?) There are certainly women who had several sets of multiples, though I don’t know that anyone ever followed through on seeing if their daughters and granddaughters did too.
FWIW my mom had 3 sets of twins. Thats not a typo; I am a twin, and have a set of twin brothers and a set of twin sisters.
And…my father is a twin.
But when I was a teenager a doctor told me that it is only the mother/woman who determines such things and the fact that my father is a twin was a coincidence.
He also said that the ‘skipping a generation’ thing was a myth.
ETA: all 3 sets of twins are fraternal. I don’t know whether my father is or not.
My grandmother had 4 sets of twin brothers and sisters. My grandfather had twin brothers. My generation was on the lookout for twins but none appeared. My sister, however, had twin granddaughters who didn’t look anything alike when they were born but within a year were identical and still are. Strange huh?
Totally anecdotal: My paternal grandfather had a twin sister. A (female) cousin of mine had (not identical) twin daughters.
This is not my field at all, so this is mostly off the top of my head. I’m more comfortable with fruit flies. However, I believe there is some real evidence that twins do run in families - that is, that there is some genetic component. This isn’t hard to imagine. If there were a mutation in some cell adhesion protein, for instance, that could make it more likely for two daughter cells to split off and be independent. I don’t know if that’s what happens - just speculation.
However, I am unaware of any genetic mechanism that can cause a trait to “skip a generation”. I think this phrase is generally used to describe either a recessive trait, which pops up more or less at random over generations, or some sort of sex-linked trait, which again isn’t always present.
It doesn’t necessarily do any skipping, though. My grandmother was the second oldest of ten, with a set of bg twins who died very young being #9 & #10. Of kids #3-8, two, a brother and a sister, each had a set of bb twins. None of siblings who made it to adulthood had twin grandchildren, and no one in my generation has kids yet.
And if she did wouldn’t she experiance menopause much earlier than usual?
Women aren’t born with the exact number of eggs they’ll ovulate, and don’t go into menopause because they’ve run out of eggs. They’re born with many thousands of eggs, most of which die before they’re ovulated. You might want to review The Perfect Master’s related column.
Considering we’re each born with tens of thousand ova, I doubt it.