If PGD (preimplantation genetic diagnosis) is to be used as well, egg fertilization is done via ICSI to avoid harmful interferences with PGD outcomes.
In IVF procedures, a percentage of the sperms that tried to penetrate the egg remain adhered to its surface. Because of that, some of their genetic material can be dragged during the embryo biopsy for PGD, which could alter the final result of this technique.
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