If you or your partner comes from a family that's brimming with twins, you may be wondering whether that might influence your chance of having twins or multiples. The answer: It does — but only in certain cases.

Here's what you need to know about the science behind family heredity and twins.

Are twins hereditary?

Yes, some types of twins are hereditary, meaning that twins run in families.

Heredity on the female parent'due south side ups a couple's odds of conceiving congenial twins. Fraternal twins are two babies from two different eggs that were released from the ovaries simultaneously.

Some research has found that having fraternal twins in a mother's immediate family may double the chances of conceiving fraternal twins. One theory is that it'southward because a certain gene may predispose some women to "hyperovulation," or releasing more than than one egg during each menstrual cycle. Women with this gene announced to have naturally higher levels of particular hormones, including those related to the regulation of releasing eggs.

However, few genes appear to be definitively linked to hyperovulation, so it could just be that genetics in full general on the mother's side contribute to the probability of having fraternal twins.

Heredity on the father's side, on the other hand, does not increment a couple'due south odds of having twins. This is true even if his family is packed with multiples.

What nigh identical twins, or ii babies who accept an identical set of genes because they're from one fertilized embryo that splits in two? Most cases of identical twins don't appear to run in families and instead seem to be a spontaneous occurrence, say experts. But there are some families with a larger-than-usual number of identical twins, suggesting there may be a genetic link.

Simply such a link hasn't been proven definitively. In other words, there's no hard bear witness that existence from a family with identical twins has an bear upon on your probability of having identical twins yourself.

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Practise twins skip a generation?

If you've heard that twins skip a generation, the theory goes like this: If there is a hyperovulation gene and a man inherits information technology from his mother, he may pass this gene on to his daughter. His girl, in plough, is then more likely to release more than 1 egg when she ovulates and therefore could excogitate fraternal twins. So the twins could have, in essence, skipped a generation.

Withal, considering there aren't any definitive links between genes and hyperovulation and because twins don't predictably always skip a generation, it'south probable just a coincidence when it does occur. In reality, in that location is no solid testify that twins skip a generation. So that notion is zippo more than a colorful myth.

How likely is it that you lot'll have twins?

Near 3.2 percent of all alive births in the U.Southward. in 2022 were to twins. So in that location's near a iii.two percent chance that you'll conceive twins.

Merely a few factors — non just heredity — can up the chances of having twins, including the following characteristics in the mother:

  • She is 35 or older
  • She is overweight
  • She's taking fertility treatments
  • She's Black
  • This is not her offset pregnancy, especially if she's previously been pregnant with multiples

Then take a adept look at your family tree. If it's full of identical twins, or there are twins on the begetter'southward side but not the mother's, twins may not be in your future. But if in that location are fraternal twins on the female parent'due south side, yous may desire to start stocking upward on ii of everything on your baby registry.