What is it that separates fraternal twins or dizygotic twins from the identical or monozygotic counterparts? Read on to explore some facts about non-identical twins.

What Are Fraternal Twins

What comes to your mind when you think of twins? Those look-alike siblings, born at the same time to the same mother, isn’t it? No, not always! They may be born approximately at the same time to the same mother, but they may not always be look-alikes. They may possess absolutely different facial features, body types, hair types and even hair and eye color. These kinds of twins are called the fraternal twins. The occurrence of fraternal twins is more common to parenting twins. The major fact governing fraternal twins is that the possibility of their birth is largely governed by genetic factors. This theory doesn’t hold ground with identical twins though. Also, as against sheer chance that governs the conception of identical twins, fraternal twins are conceived when the mother hyper ovulates, that is she ovulates more than one egg during her cycle. Two separate sperms fertilize two different eggs which lead to the birth of fraternal twins. Multi-fertility pills can also be the reason for multiple pregnancy to occur. But first a look at the basic facts of fraternal twins!
Information On Fraternal Twins
  • A major reason for multiple conceptions is a phenomenon called superfetation. In this condition, an already pregnant woman ovulates and releases another egg. And this egg is then further fertilized by a sperm. But this phenomenon cannot occur at all times. It can only occur up to 24 days after the release of the first egg. This means that the babies would be born on the same day, despite developmental differences, owing to different dates of conception.
  • Fraternal twins as a phenomenon is way more common than the identical twins phenomenon. It is said that of the total global twin births, approximately two-thirds result in fraternal or what is commonly known as non-identical twins.
  • Fraternal twins are a genetic phenomenon. Their chances are high when the mother herself is a fraternal twin in which case the possibility of giving birth to fraternal twins is said to be as high as one in seventeen.
  • Another interesting information that has come up in the global researches carried out on fraternal twins is that their chances skyrocket if the couple has been on fertility treatments.
  • Also women trying to conceive after 35 years of age are more prone to fraternal pregnancies than the younger ones.
  • On a closer look at the geographical distribution of fraternal twins, the statistics indicate that Africa witnesses the highest number of fraternal twins, while Asia witnesses the lowest.
  • The number of pregnancies also has an impact. More the number of pregnancies a woman has, higher become her chances of giving birth to fraternal twins.
  • Some studies also link fraternal twins with mother’s height. They suggest that taller women are more likely to have twins as compared to petite ones.
  • Fraternal twins aren’t identical fails to hold grounds with the researchers all the time. Since fraternal twins share about 50% of their genetic makeup, they can both be as similar as identical twins or absolutely non-identical like ordinary siblings.
  • Another rather unbelievable fact about fraternal twins is that they can belong to different fathers too. That happens in the case of superfetation, where as explained earlier, a pair of twins can be conceived at different times, but be delivered at the same time.
  • Only the mother’s genetic makeup can have an impact on her capability of having fraternal twins. A couple can have fraternal twins if the mother is a fraternal twin herself, but there is no such research that suggests that the father being a fraternal twin can impact the pregnancy.

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