Oocytes and sperm differ significantly from any other part of the body by one feature: they contain only half a set of DNA. The purpose of this is to allow the mother or father to bring in half of his DNA and thus create a human who gets half of both parents on their way.
Of course, that happened at the beginning of the father and the mother of the child - so there are almost infinite combinations in which half the DNA set can be present. In one reproductive cell, for example, the predisposition to blond, the other to red hair may be included.
Fertilization is only possible if the wife and husband have sexual intercourse on the fertile days of the woman. These are the days just before ovulation and during the migration of an egg through the fallopian tube to the uterus.
Sperm move on their own, with recent observations suggesting that only a few sperm are ever thought to fertilize the egg. All the others in the network ensure that these sperm are transported forwards to the egg.
A single sperm penetrates through the outer shell of the egg and penetrates to the cell nucleus. With this, the nucleus of the sperm, which in the meantime has triggered its scourge, merges - fertilization is complete. The ovum now only changes its cell skin, so that no more sperm can penetrate more.
Fertilization is the basis of human reproduction. If she does not or not properly, the woman can not get pregnant and have no child.
About every 28 days, a new egg is ready for fertilization, waiting for her to progress from ovary to uterus to male sperm that can fertilize her. The fertilization must happen without errors, because with it the DNA of the parents is passed on and recombined, it holds a high error potential.
Risks begin with the development of eggs and spermatozoa and ends in response to external influences such as radiation during fertilization, which can affect them and cell division that occurs afterwards. Important for the woman in the fertilization is the presence of a healthy mucous membrane in the uterus, otherwise the egg can not implant. There would be no pregnancy. In man, fertilization depends heavily on the quality of the sperm so that it works smoothly.
Normally, the woman does not notice much of the fertilization. The first sign is often just the absence of monthly bleeding. If, on the other hand, the ovum has taken root, fertilization has been successful, but some women quickly develop the first symptoms of early pregnancy.
Age of the parents, their way of life and external influences such as radioactive radiation or diseases of the parents can strongly influence the fertilization. It is a particularly crucial point in pregnancy and also in the life of the child to come, as DNA plays a major role here. If an egg or a sperm splits incorrectly or if an error occurs during the fusion of the two cell nuclei, a more or less severe congenital disorder can occur.
Unfortunately, neither a woman nor a man has much influence on this - there are only examinations of the embryo to determine his health. Particularly well-known illnesses, which develop from errors of the DNA with the fertilization out, are the down syndrome or metabolic diseases like the phenylketonuria, which make the child almost always the everyday life more difficult.
If a serious mistake happens during fertilization, sometimes the woman's body already recognizes that. The fertilized egg can partially nest and the woman thus notices her pregnancy, but it comes soon after a abortion. It is similar to a menstrual period and is therefore sometimes not recognized as an abortion. Since there is no health threat for the woman, this does not have to be taken care of medically, if everything runs without complications.
Especially with older parents problems in fertilization can be due to the fact that sperm and eggs change qualitatively. Modern medicine knows meanwhile methods of the artificial insemination, which proved to be very efficient, if woman or man developed problems with the fertilization.
Often the underlying problem is no longer treated but directly artificially fertilized. The procedure is often used to treat hormonal problems during fertilization, sometimes with women's hormone therapy, to enable healthy pregnancy after fertilization. Very few problems with fertilization today really lead to unwanted childlessness, most treat themselves well.Tags: