There is a special beauty in pregnancy. The promise of a new life in a woman's body looks very life-affirming. Complex processes take place inside at all stages of the "interesting situation". It is not always possible to determine the exact day of conception. The doctor will record in the documents the first day of the last menstruation as the beginning of pregnancy. Although, in fact, a new life begins about two weeks later than the deadline formally fixed in the papers. How does conception occur?
Preparation stage
It all starts with ovulation. Every month, several “candidates” prepare for release in the ovary, but, as a rule, only one egg comes out, occasionally two. If more than one comes out and both are fertilized, then fraternal twins will be born. Strictly speaking, they are not twins at all. And they will look like two children of the same parents.
16 kids at once?
Howis the conception of true twins? Like any other, but for some reason, at a certain stage, several embryos with the same genetic code are formed. Theoretically, a person can have as many as 16 twins at a time, since at the stage of 16 blastomeres, each cell can give rise to a whole organism. But a huge number of twins at once is usually due to fertility treatment, it is not normal for a person to conceive more than two children at the same time.
Exceptional cases
By the way, contrary to popular belief, a boy and a girl cannot be true twins, because men and women have a different genetic set, and the set of twins is identical. The only exception, theoretically possible: two children are genetically boys, but in one of them, intrauterine development went wrong, and in a girl, the formed sex does not correspond to the present. Such "girls" are sterile.
Permission denied
How does conception happen? After the egg is released in the fallopian tube, it may meet the waiting sperm. But usually there are millions of them. Not every one of them can fertilize a cell. Scientists have found that each egg has a certain “access code”, which manifests itself in the chemical structure of the protein at the outer border. If the sperm cell has the “correct” code on the shell, then fertilization can take place. After the penetration of the male cell inside, the egg becomes inactive and inaccessible to other "candidates".
Biochemistry is to blame
The female cell is so arranged that before fertilization it is not complete - the process of meiosis ends only after the start of interaction with the spermatozoon. If a meeting with a worthy "partner" does not occur, then the egg is destroyed, the hormonal status changes - and menstruation begins. Knowing how conception occurs helps explain the infertility of some couples in which the partners seem to be both he althy. In such cases, the husband and wife are incompatible at the biochemical level. If they create families with other partners, then both can have children safely.
There are many secrets in the process of conception. We do not know all the regularities of what is happening. But one thing is clear – more research on conception is needed. Then there will be an opportunity to help couples suffering from infertility.
