| No. A woman ovulates once each menstrual cycle. For most women, a menstrual cycle lasts about a month. However, if the woman has very brief cycles — 21 days or so — she may ovulate twice in a calendar month, but still only once in each menstrual cycle.
The birth of fraternal twins does not indicate two instances of ovulation in a menstrual cycle. Fraternal twins result from the fertilization of two eggs that are released in the same instance of ovulation — during the same menstrual cycle. Each egg is fertilized by a different sperm. (In the instance of identical twins, there is only one egg and one sperm. Identical twins result when a single fertilized egg divides into two separate pre-embryos very early in its development.)
Because it is not uncommon for one fraternal twin to be bigger than the other, there is a folk belief that the larger of the twins is "older." But this is a mistaken belief. No matter the size difference, both fraternal twins have developed from eggs that were released at the same time, each fertilized by a different sperm.
To sum up: Ovulation — the release of an egg from the ovary into the fallopian tube — takes place once in each cycle. Ovulation most often occurs 14 days before the onset of menstruation.
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