Epub Apr Pubmed: A genome wide linkage scan for dizygotic twinning in families of mothers of dizygotic twins. Hum Reprod. Epub Apr 8. Shur N. The genetics of twinning: from splitting eggs to breaking paradigms.
Other chapters in Help Me Understand Genetics. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. The occurrence of identical multiples are of mere chance, and unfortunately have no way of being perviously detected until the mother is given an ultrasound.
So the verdict? Fraternal twins can run in families where identical twins are likely a coincidence, and the idea that twins can skip a generation is simply just a myth. I also was under the impression that having twins skipped a generation. Since my mom is a twin I was always under the impression that I or my sister would be next.
But identical twins don't. Non-identical twins are the result of two separate eggs being fertilised by two separate sperm. There is a gene that makes a woman more likely to release two or more eggs during ovulation, and it's this gene that runs in families. Identical twins are the result of a single fertilised egg splitting, and this seems to be a random event.
So if you're a woman and non-identical twins run in your family, you're more likely to have a set yourself. It's estimated that you're about two and a half times more likely than average to have twins if you're a non-identical twin, or have siblings who are non-identical twins. References This article has been written using the following sources: Hall JE. Endocrinology of the menopause.
Endocrinol Metab Clin North Am 44 3 Fertility treatment in trends and figures. Human Fertilisation and Embryology Authority. Fertility: assessment and treatment for people with fertility problems. Men, of course, don't ovulate, so even if they've inherited that hyperovulation gene from their parents, it doesn't increase their own odds of conceiving twins.
You may have heard that twins 'skip a generation'. While it's not a blanket true statement, it is actually based on some truth. Here's how: we know that twinning is due to factors on the woman's side, like hyperovulation. But it takes two to make a baby, or babies in our case! This is where the skipping is relevant. If a man has inherited the hyperovulation gene from his mother, he may pass this gene on to his daughter, but it won't impact on the chances of him conceiving multiples with his own partner.
Men, of course, don't ovulate, so the chance of twins or more is up to the woman.
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