Do Identical Twins Run in Families? Identical twins are typically not hereditary like fraternal twins and occur in three to four births out of every 1,000 globally. A few families report a higher level of identical twins than expected, so there may be a genetic factor in rare cases.
As such, fraternal twins are hereditary but only if the gene is passed down from a parent to their female child. So, even if a male has twins in his family, it won't increase the chances of having di-di twins as a couple unless the mother has twins in her family as well.
Approximately 10% of Di/Di twins will be monozygotic, resulting from the early splitting (within the first 3 days) of a single embryo. Both fetuses will have arisen from the same egg and sperm, and therefore, will be genetically identical (and have the same sex as confirmed by ultrasound).
The quick answer to this question is that, in a twin pregnancy, it is the mother's genes that determine twins. First up, giving birth to identical twins is not genetic, but conceiving fraternal twins is. The mother may have the genetic trait of releasing two eggs in one menstrual cycle.
Identical twins do not run in families. But there are some factors that make having non-identical twins more likely: non-identical twins are more common in some ethnic groups, with the highest rate among Nigerians and the lowest among Japanese.
The notion that twins always skip a generation is also a myth. The illusion may have arisen because men who inherit the gene from their mothers are unaffected by it ( they do not ovulate), but can still pass it on to their daughters, who, in turn, will have an increased likelihood of conceiving twins.
Identical twins are almost always the same sex, although there are some rare exceptions to this rule. Because identical twins occur when a single fertilized egg splits and forms two embryos, each embryo has the same chromosomes (usually, XX for girls or XY for boys).
Dizygotic (DZ) twins, also called fraternal twins, occur when two egg cells are each fertilized by a different sperm cell in the same menstrual cycle. DZ twins are about twice as common as MZ twins, and they are much more likely to run in families.
According to Stanford, the likelihood of twins during any particular pregnancy comes from the mother, because, as they put it, "A father's genes can't make a woman release two eggs." If you're the woman who is trying to conceive though, it's not just your mom's genetics that matter.
Factors that increase the chance of twins include: consuming high amounts of dairy foods, being over the age of 30, and conceiving while breastfeeding. Many fertility drugs including Clomid, Gonal-F, and Follistim also increase the odds of a twin pregnancy.
Monoamniotic-monochorionic Twins
This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords. If you have monoamniotic-monochorionic twins, your healthcare provider will monitor your pregnancy closely.
Sometimes health care professionals identify same-sex twins as fraternal or identical based on ultrasound findings or by examining the membranes at the time of delivery. The best way to determine if twins are identical or fraternal is by examining each child's DNA.
Mo-Mo twins should always be delivered by cesarean section to avoid umbilical cord complications for the non-presenting twin at the time of the first twin's delivery. A woman carrying Di-Di or Mo-Di twins is a good candidate for a vaginal birth if: The presenting twin is in a vertex position.
Di-di twins each have their own placentas and amniotic sacs, sharing only the womb to develop. This puts them at the least risk out of all the kinds of twins, but there are still some things to know if you are having them.
Twins and triplets often don't have a chance to reach a healthy weight before they're born. While the average single baby weighs 7 pounds at birth, the average twin weighs 5.5 pounds. Triplets typically weigh 4 pounds each, and quads weigh 3 pounds each.
Monozygotic (identical) twins will have the same blood type, with a few very rare exceptions. Dizygotic (fraternal) twins may have the same blood type, or they may have different types.
A dad who's one of a twin may inherit the gene, but it won't increase his chances of having twins too, because the gene only affects ovulation. The same dad may pass on the gene to his daughter, who then goes on to get pregnant with twins, making it look like twins have skipped a generation .
Some parents utilize color coding. They consistently dress each twin in a designated color. For boy/girl twins, the color combination of choice may be blue/pink; for two girls, perhaps purple and pink, and for two boys, blue and green. You can have fun with it.
They come from the same fertilized egg and share the same genetic blueprint. To a standard DNA test, they are indistinguishable. But any forensics expert will tell you that there is at least one surefire way to tell them apart: identical twins do not have matching fingerprints.
Identical (i.e., monozygotic, or MZ) twins share 100 percent of their genes, whereas fraternal (i.e., dizygotic, or DZ) twins generally share only 50 percent of their genes.
Fraternal Twins: This type of twin set is the most common. This occurs when two different eggs are both fertilized by two different sperm and implant themselves into the uterine wall at the same time. Fraternal twins will both have a different amniotic sac and placenta.
There are more twins in the "millennial generation" than any other generation, thanks partly to a twin boom in the '90s. The main reason was a new technology called in vitro fertilization, which in its early days frequently produced twins, triplets and other multiple births.
The first wife (died ante 1770), of Feodor Vassilyev (b. 1707–c. 1782), a peasant from Shuya, Russia, gave birth to 16 sets of twins.
The term “Irish twins” refers to siblings who are born within 12 months of one another. This is especially true for children born in the same calendar year, or children who would be in the same grade of school. However, children born within 18 months of one another are still often referred to as Irish Twins.