The reasons for the birth of twins

Several centuries ago, the birth of two or more toddlers from a woman was recognized as something supernatural, but today the doctors found this explanation a lot of explanations.

The reasons for the birth of twins can be as follows:

1. Heredity, since in 10% of cases such babies appear in those families where twins were already born. In this case, everything can be explained by genetic predisposition, as a woman produces a large number of hormones, which stimulates the maturation of several eggs at once, thereby increasing the probability of conception of several babies at once.
2. The abolition of oral contraceptives that block ovulation and monthly maturation of female cells often leads to the release of several cells at once, especially in the first month, as the body tries to "catch up".
3. Treatment of infertility with drugs that stimulate ovulation, gives the same effect.
4. When using in vitro fertilization, women are often "planted" several embryos at once to increase the chances of pregnancy, and it happens that all or most of these embryos begin to develop successfully in the uterus.
5. Physiological features of mother, in particular, bifurcation of the uterus, can lead to the conception of twins.
6. Age of the mother, as the older she is, the greater the chance of giving birth to twins.
7. Repeated delivery, as each new pregnancy is more likely to result in the birth of twins. If a woman has already produced two babies, then this probability is doubled.

In addition, studies show that during periods of wars and social upheavals, the frequency of the birth of such babies increases. This fact does not find an explanation, and scientists can only assume that the natural mechanism of preserving the human race works in this way.

It can be noted that all of the above reasons make it possible to explain why twins appear - unlike kids, sometimes even of different sexes. At the same time, science is not yet able to explain why absolutely identical children are born (true twins).

What are the twins?

So, by universal delusion, kids do not always look like each other like two drops of water. Gemini can be dizygotic and monozygotic, which differ from each other by the mechanism of conception.

Dizygotic babies are born when several eggs were fertilized at the same time by different spermatozoa, and therefore externally they are completely different and may even have different sexes.

The causes of the appearance of monozygotic (identical) twins are the following: one sperm fertilized one sperm, but after a while (from 2 to 12 days) the zygote was divided into two (and sometimes even more) embryos. That's why these babies are always absolutely identical, both genetically, externally, and sex. Doctors noticed an interesting pattern, which consists in the fact that the earlier the division of the zygote begins, the less common will the odnoyaytsevyh kids.

Siamese twins and the reasons for their appearance

The reason for the birth of Siamese twins is the following: when one egg is impregnated with one spermatozoon and later, too late (after the 12th day after fertilization) is divided into two parts, it happens that embryos do not have time to completely separate, having started an active individual development. In this case, they remain attached to each other by one or another part of the body (this may be a common head, abdomen, limbs, face).