The desire to have children leads many couples with fertility problems to resort to artificial techniques such as assisted reproduction. Although in Italy this technique is still the subject of strong discussion, research continues to make progress to ensure the success of embryo implantation. Before implantation in the maternal uterus, the embryos are analyzed and those that can be used are selected, in order to distinguish the healthy from the sick. However, a recent discovery has shown that not all diseased embryos need to be discarded, some can be used by increasing the chances of successful artificial insemination.

Assisted fertilization is the process that artificially mediates the union of egg and sperm, also called gametes, allowing fertilization.
When the semen and the egg belong to the child's parent couple, we speak of homologous fertilization; I know, instead, the seed or egg belongs to a person unrelated to the couple, we speak of heterologous fertilization.
After the first implant, other unused embryos can be frozen in liquid nitrogen for five years, in case the couple wants to undergo the same treatment again.

Not all diseased embryos are unusable, in fact, some researchers from the European Hospital in Rome have discovered that it is possible to obtain healthy children from diseased embryos. These embryos are carriers of a chromosomal abnormality that prevents implantation success and causes spontaneous abortions, therefore such embryos are discarded.
The anomaly is called "mosaic aneuploidy", it is a malformation in which part of the embryonic cells have an altered number of chromosomes, but not all, in fact, healthy and diseased cells coexist within the embryo. This deduction led us to think that the embryo was repairing itself, therefore the diseased cells would be confined to the region where the appendages are formed such as the placenta, without causing any damage.

In this study they were analyzed 3800 blastocisti (the set of cells that are formed in the first two weeks of fertilization), of which the 5% they were mosaic. They have been chosen 18 couples in which to implant the mosaic embryos, taking into consideration only those who presented anomalies that did not allow to carry the pregnancy to term, therefore there was no risk of generating sick children.

Research, published in the New England Journal of Medicine (NEJM), allowed the birth of six healthy babies, showing that these embryos can be used for assisted fertilization. [GM]