The typical question is usually: “whatAre twins or fraternal twins?” Because believe it or not, there are many more categories within this world. So here we present to you the more bizarre instances.
10 rare Types of twins
1 – The twins in mirror
These are, without a doubt, the most common type of twins rare, because one out of every four pairs of identical twins are identified as such. They are also considerably easier to detect than other types.
Twins in mirror are opposed to each other. One is left-handed and the other right-handed, and even their physical defects genetic appear on opposite side. This occurs when the zygote is divided between 7 and 12 days.
2 – a pair of Twins, almost identical, or polar bodies
They are a form of theoretical twins who have never been documented by science.
The theory states that the twins polar body is formed when an egg descends and then splits in two. The smaller of the two new zygotes is called a polar body, which rarely survive due to the lack of cytoplasm.
If both the primary and the polar body were fertilized, the result would be twins, only that they would share 75 percent of their genetics, not the usual 50% of the twins.
3 – a pair of Twins semi-identical
Identical twins form when one sperm penetrates into an egg, and in the early stages of development, the egg divides in two. Since it was the same sperm and the same egg, the result is that their genetic composition is identical.
But what if two sperm were able to enter the egg at the same time? The first case was documented in 2007. Each twin gets a bit of the dna of each sperm, so that they are half-brothers and half-identical.
4 – Turner Syndrome
The sex of identical twins is as random as it would be with any normal pregnancy. When an egg is fertilized, the sex is determined right away, and the egg split later in two children of the same sex.
However, a medical condition that can cause identical twins to be born different sexes. Turner syndrome occurs when a developing fetus loses its second chromosome due to genetic abnormalities.
Women with Turner syndrome often have problems of development and reproduction as they grow older, which means that the phenomenon is usually identified with the time.
5 – Superfecundación heteropaternal
It is a rare type of twins, not so much because of the genetic factors involved, but by the mating habits of human beings. Occurs when two eggs from a woman are fertilized by different men.
It is very common in other species, such as cats.
6 – Superfetación
The superfetacion is the phenomenon by which a woman becomes pregnant, when he already is. Has been recorded only ten cases in the history.
What makes the superfetación so rare is that it requires the body to work in one of two ways very specific. In the first place, the uterus has to stay open for more than ten business days. And, besides that, the second egg has to go down sooner than expected.
The biggest risk with superfetación is the second baby to be born prematurely when the mother of birth to the first child, but as children are conceived with a short-period difference, this is not a significant problem.
7 – Twins of a different mother
Believe it or not, identical twins can also have different mothers. Is known only one case. After struggling for 12 years to get to his second son, a woman decided to undergo fertilization in vitro and to an belly subrogation. Against all the odds, the fertilized eggs settled on the two women.
8 – Twins birraciales
The twins birraciales, in which each one is of a race, can take three different forms: or when parents of different races have twins, when it occurs superfecundación heteropaternal or when two people of mixed race have twins.
9 – Twins parasite
The twins parasites are a form of twins states, which occurs when a fertilized egg does not divide properly. The twin parasite is smaller, is not completely formed and is not a conscious being.
The twins parasites can develop in any part of the body and can occur in a variety of forms, from a small bulge to a second head.
10 – Chimeras
Identical twins occur when one fertilized egg divides in two. In the case of the chimeras, they being twins, with two eggs separated, but in a moment of pregnancy, the two fertilized eggs join together, resulting in one person with two distinct sets of DNA.
The different sets of DNA, that can even be of different sexes are located in various parts of the body so that a test of your blood may give different results.