This is a very interesting question which asks if we can assess the oocyte quality before fertilization. Obviously, an oocyte is a very valuable cell. We cannot manipulate it. If we manipulate it, we fall into a paradigm and a contradiction. Once an egg is manipulated, we can’t use it. Either we know about the molecular mechanisms of the oocyte and then we cannot follow up the development of the cell because we would need to kill the cell to know the molecular mechanisms or we can just assess, without any intervention, in order to be able to use this cell and to have information of the follow-up of its biological behaviour. This dilemma will always be there. All this information we have on egg quality is based on non-invasive technologies. Otherwise, we would not be able to follow up on the development of the cell. This is, obviously, a big restriction. We can only have indirect data. This is true that there are some attempts with artificial intelligence and big data involving screening the oocytes on different depths in 3D and taking high-resolution pictures. This procedure is non-invasive and preserves the viability of the cell. It also gives us a lot of information that we can cross-examine with the behaviour of these oocytes once fertilized. This is a very promising technology because we could identify some structures that are not visible to the human eye, advanced microscopes that use polarized light, or even fluorescence. This data, pictures of a cell, can predict if this cell can get fertilized properly or not if an embryo resulting from this cell will have a good chance to proceed to blastocyst or even if the clinical outcome of this embryo will be positive or not. Obviously, this research has just started and there are a couple of scientific studies that approach this topic but this looks very promising. This is nothing we are now using routinely at clinics but I hope this is a technology that will be available in a couple of years’ time. This is interesting only for countries where it is not allowed to fertilize all eggs, like in former times in Switzerland or Germany or other countries around the world where there are restrictions for generating embryos for each cycle. In Germany, for example, they fertilize the eggs and then freeze them in the pro-nuclear status before they can be defined as an embryo. But, in this case, it would be very useful to have a tool that can predict if an egg is competent or not and then we should rely on these artificial intelligence tools that will be coming in the next years. So far they are not ready. There are also some other approaches like analysing the follicular fluid of each oocyte or the cumulus cells that surround the oocyte inside the follicle that after aspiration we can also assess under the microscope. There are several scientific works regarding analysing these cumulus cells, factors that they extrude in the follicular fluid in order to have a molecular fingerprint of these oocytes that will tell us if it is a competent oocyte or not. This was done in France a couple of years ago, also there are some Canadian works on this that look very promising. To conclude, for most cases and most countries it is not that interesting to check the oocyte quality before fertilization because we will see the oocyte quality after fertilization through the embryo quality. This is the strongest factor. The oocyte quality contributes in more than 80% to the embryo quality and it drives and runs the first three days of embryo development, up to 8 cells until the embryo gets autonomous in the so-called zygotic activation. After that, the embryo takes control over the cell division itself. But before, everything is run by the oocyte. So that is why it is not interesting to look at the oocyte, not at the embryo in countries where it is allowed. But knowing this and knowing the restrictions we have in the molecular analysis of the oocyte, knowing that we can have high resolution images, knowing about the cumulus cells and follicular fluid can tell us something about the biological competence of cells is, for sure, interesting. In some countries it could really be a key to the selection of these oocytes before fertilization, oocytes that we would prefer to fertilize in order to generate the best possible embryos in the first run, not just by chance.