People tend to confuse such concepts as twins and twins. Many simply do not know how these children are different. There are some differences in terms of medicine. The article will allow to stop confusing in such concepts. Especially this information is important for people in whose family such babies have appeared.
- Concept in medicine
- Identical twins
- Miscellaneous twins
- Polar twins
- Siamese twins
- Reasons for
- What distinguishes
- Things like
Concept in medicine
It should be noted that in medicine there is no such thing as twins. There are such terms as identical twins and fraternal twins. In everyday life it is the raznoyaytsevye twins are often called twins.
to table of contents ^Similar twins
Such twins appear due to the separation of an already fertilized egg. One egg leaves the follicle, and it is fertilized by one sperm cell. Then there is a division of the fertilized egg into two. After this separation, two children with the same set of chromosomes are born. These children are very similar to each other. It often happens that even parents do not distinguish between twins.
Tethered twins
Such twins are born if two ovules come out of the follicle at once. This phenomenon is usually determined genetically. If a woman in the family already had twins, if the woman herself has a sister or twin brother, then she has a tendency to give birth to such twins. Two eggs are fertilized with two different spermatozoa. Thus, the fraternal twins have a different set of chromosomes. They can be of different sexes, they can be similar, but no more than children from one parent are like.
to contents ^Polar twins
The above options are not the only ones allowed. Between them, another intermediate option is possible. This biological phenomenon is called polar twins. Such twins are usually born very rarely. This is due to the fact that the process of conception of such children is very complicated. Sometimes in the body of a woman there is a polar body. With a rather high probability of such a body dies, and pregnancy does not occur. In very rare cases, it behaves like a full-fledged egg. Such polar twins have fairly pronounced external similarities, but at the same time they can be of different sexes. In connection with chimerism( a combination of two different DNA), polar twins may have a mixed genotype.
to table of contents ^Siamese twins
It is important to mention and such pathology as Siamese twins. This pathology occurs when a fertilized egg begins to divide, but does not separate normally. Sometimes these children can be divided surgically. In some cases, such a separation is impossible. Not all such children survive even before adulthood. Nevertheless, there are well-known Siamese twins who could live a long enough life.
to table of contents ^Reasons for
Often twins are born if the conception of children occurred with the help of IVF technology. This is due to the fact that all embryos do not always survive. That's why doctors for reinsurance plant 2-3 embryos. Sometimes it happens that everyone survives. That is why a pregnancy that occurs with the use of ECO-technology, is often prolific.
Thus, we can sum up three reasons, in connection with which a woman can give birth to twins. But for what reason is the division of the already fertilized egg, scientists are not yet known. Accordingly, identical women can give birth to identical twins, and the birth of such children can not be predicted.
Nevertheless, the cases of the birth of identical twins are quite rare. Usually for 3-4 thousand births, in which one child is born, there are only 1 birth, in which identical twins appear. But twins are born much more often, usually here the ratio of 1 to 90 genera.
to table of contents ^What is the difference between
What is the difference between twins from twins? This question is asked by many parents who have such children.
- The raznoyaytsevye twins can be of different sexes. Identical twins are usually same-sex.
- In theory, there is a possibility that twins can be conceived from different fathers. Of course, in a monogamous relationship, a twin usually has one father. However, in some situations this situation is possible. In identical twins, the father is always one.
- identical twins are necessarily similar to each other. The different twin twins have some differences in appearance.
- They always have one blood group and the same Rh factor. In rabbits, these figures may differ.
- Children's development. Twins usually have two placentas, but identical twins have one placenta for two.
Than similar
- Both monotonous and differently identical twins are very similar among themselves in the childhood. The similarity of identical twins can be so great that even their parents do not distinguish between them. The similarity between the twins is somewhat lower, however, it is high enough. This is due to the fact that children are conceived from one parent, have a similar set of genes and are born simultaneously.
- Most often these children can be donors to each other. Of course, identical twins are completely identical, they are the best donors for each other. Nevertheless, even twins are good enough donors due to the fact that they are close relatives.
Despite the fact that twins are similar in many ways, they should still be regarded as different people. In history, there are cases when identical twins were separated in early childhood, and they were brought up in different families. However, their fates are similar in many respects - starting with the names of the spouses and ending with the profession and the number of children. Most likely, such cases are explained by similar genes, scientists have no common opinion on this matter.