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.
However, few genes appear to be definitively linked to hyperovulation, so it could just be that genetics in general on the mother's side contribute to the probability of having fraternal twins. Heredity on the father's side, on the other hand, does not increase a couple's odds of having twins.
However, since only women ovulate, the connection is only valid on the mother's side of the family. While men can carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves.
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 .
This belief is based on the assumption that twinning is genetic and runs in families. However, if that was truly the case—if there was a twin gene—then twins would occur with predictable frequency in those families that carry the gene. There is no concrete scientific evidence that suggests twins skip a generation.
The gene versions that increase the chance of hyperovulation can be passed down from parent to child. This is why fraternal twins run in families. However, only women ovulate. So, the mother's genes control this and the fathers don't.
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.
if you're pregnant and over 35 you're more likely to have non-identical twins because you're more likely to release more than 1 egg during ovulation. non-identical twins run on the mother's side of the family, probably because of an inherited tendency to release more than 1 egg.
In prenatal ultrasounds, the baby positioned lowest in the uterus is given the designation of “Baby A.” Under this convention, Baby A will likely be born first in a vaginal delivery. However, about 75 percent of twins are delivered by cesarean section.
In contrast, identical twins (or monozygotic twins) result from the fertilization of a single egg by a single sperm, with the fertilized egg then splitting into two. As a result, identical twins share the same genomes and are always the same sex.
The biological phenomenon of giving birth to twins with two different biological fathers is called heteropaternal superfecundation. This happens when a second ova released during the menstrual cycle is fertilised by sperm cells of a different man from separate sexual intercourse.
If you are lucky enough to come from a family with a pattern of having twins then genetically you are more likely to as well. So if you, your mother or your maternal grandmother are or were fraternal (non-identical) twins then your chances of having twins may increase to as many as 1 in 7.
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.
"It's honestly such an insane experience. My whole life I wanted to be a mom, and so while it's tiring and stressful, at the end of the day it just feels so rewarding." The odds of the same family having two sets of fraternal twins is 1 in 12.
7.3 percent in women younger than 35. 6.9 percent in women age 35 to 37. 6.8 percent in women age 38 to 40. 5.1 percent in women age 41 to 42.
Like for their twin parents, there are many fascinating family relationships for the children of twins–when identical twins have children, their children are cousins but genetically as similar as half-siblings.
In Australia, twins happen in 1 in every 80 births. This means that 1 in 40 Australians is a twin. The birth rate of identical twins is the same around the world and doesn't vary with the mother's age.
The birth process is similar to giving birth to a single baby. If you're planning a vaginal birth, your health team may recommend that you have an epidural for pain relief.
Twins are more or less equally likely to be female or male. Contrary to popular belief, the incidence of twins doesn't skip generations.
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. Therefore, it may be concluded that twins with differing blood types are dizygotic, or fraternal.
Identical twins cannot be determined genetically since giving birth to them does not depend on genetics; however, conceiving fraternal twins can. It is possible for the mother to possess a genetic trait of releasing two eggs during one menstrual cycle which increases her chances of having fraternal twins.
Such twins, known scientifically as 'MoMo', an abbreviation for monoamniotic-monochorionic, are some of the rarest types of twins, making up less than one percent of all births in the United States, noted the statement. It also stressed that such MoMo twin pregnancies have a high risk of fetal complications.