If you are pregnant and have a family history of multiple pregnancies, you may be wondering if having twins is hereditary. Well about 17% of twins have twins themselves and it does not matter if it is the father or the mother, the one who has a brother who was born in the same childbirth.
During the first trimester of pregnancy is when you will know if you are pregnant with more than one baby, and sometimes it happens that one of the two does develop while the other does not. It is what is known as “Syndrome of the missing twin”, and occurs when the gestation of one of the eggs is interrupted before week 12. The placenta reabsorbs the missing embryo.
Types of twins
Colloquially we distinguish two types of twins, twins and twins, triplets or more. But this is really a cultural meaning, since scientifically they are identical or monozygotic twins and dizygotic twins.
Conclusion monozygotic when for unknown reasons, the same egg fertilized by a single sperm divides into two. This results in two people with identical genetic makeup. These types of twins always have the same sex.
They are dizygotic twins or twins when two or more eggs have been fertilized by one sperm each. What there is is a multiple pregnancy in which each of the fetuses has its placenta. They are different babies, who can have different sexes and with a similar resemblance to that between siblings. They share only 50% of the genes.
And once this is clarified, let's go back to the question of whether having identical twins is hereditary or not.
Is it hereditary to have identical twins?
Science does not yet have an exact answer as to how identical twins are produced, so it is difficult to make a categorical statement about whether there is a hereditary possibility that the twin pregnancy will recur in the next generation. What we do know is that the chances of having identical twins are 1 in every 250 pregnancies. The rate of identical twins is stable in the world, between 3,5 and 5 per thousand births
Those who defend that it is a hereditary issue believe that it actually comes from certain peculiarities associated with family hormonal secretion. Interestingly, twin pregnancies are more frequent in black women and less in Asia.
And then there are the mirror twins, a subset of identical twins, in which the fertilized egg divides later (9-12 days). These mirrored babies are essentially reflections of the other and will have opposite features. For example, one is almost certainly right-handed and the other left-handed.
Is it hereditary to have twins?
The case of twins is quite different from that of identical ones. There are different factors that increase the chances of having this type of multiple pregnancies. Here we can affirm that the hereditary component increases the chances by 20% when it comes to getting pregnant.
The way it is inherited This feature of multiple ovulation is from mother or father to daughter. Hence, it is thought that a generation skips. If the mother of the pregnant woman has had twins, she is twice as likely to have twins. The same is true if the girl is the niece or sister of someone who has had twins. If the father is the twin or comes from a family of twins, he can pass the gene on to his daughter or son. And this son will be the one to transmit it to his future daughter, hence the popular belief is that a generation is skipped.
A curiosity is that in the women of the Yoruba tribe (of Nigeria) 45% of the births are multiple. Studies indicate that the staple diet of this tribe, a sweet potato, may be the cause.
If you want to know more about raising twin babies, we recommend you this article.