Facts about Fraternal Twins
Fraternal twins are the most common type
of twinning, also known as Dizygotic or Non-Identical Twins. This
happens when two eggs have been released called hyperovulation, which
are then fertilized independently, by two separate sperm.
Here are more facts about non-identical twins:
- Dizygotic Twins are more common than identical twins.
The most common is boy/girl twins which makes up nearly half of all
twins born, about 40%. In total non-identical twins make up about 75% of all
twin births. Next in order of most to least common are fraternal girls,
fraternal boys, identical girls then identical boys.
- They each have their very own placenta but sometimes
the two placentas can become fused together. But they will always have
their own amniotic sac.
- Looking geographically Africa has the highest
incidences of dizygotic twinning while Asia has the lowest. People say
in some African tribes the consumption of yams has some effect on
- While identical twins are in no way heredity,
dizygotic twinning can run in the family. In saying that there are women
who fall pregnant with dizygotic twins with no history of multiples in
- It is more common for older women to fall pregnant
with non-identical multiples. Of mothers who become pregnant over the
age of 45, 17% of those have multiples. Other factors that researchers
have said to increase the likelihood of having twins are women who are
taller, who have had a number on pregnancies and women who are
- Fraternal twins are siblings that share a birthday.
Though they share about 50% of their genes, they can look very different
or can sometimes be mistaken for monozygotic, identical twins.
- Fertility drugs and treatments can increase the chance of having twins.
- Once you have had non-identical twins then you are twice as likely to have them again.
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