Trophectoderm (TE) biopsy is the gold standard for collecting embryo specimens for pre-implantation genetic testing (PGT). Because TE biopsies contain approximately 5–10 cells they provide a more robust template for DNA amplification, increasing diagnostic efficiency and representativeness of the whole embryo chromosomal constitution compared to a single cell biopsy. TE biopsy requires superior micromanipulation skills. Technical aspects include the combination of laser technology and micromanipulation to detach the biopsied specimen from the blastocyst. TE biopsy can be achieved employing different approaches according to the blastocyst’s characteristics and laboratory setting. Biopsy tubing entails a high degree of manual skills and coordination. In order to reach a highly efficient PGT program, blastocyst culture, biopsy and tubing technique, as well as robust cryopreservation processes are required.

Genetic risk is defined as the probability of a person (or couple) conceiving a pregnancy with genetic mutations or chromosomal abnormalities that would lead to a severe pathological condition. Genetic mutations are concealed in the genome of almost every person. Most of these mutations are harmless in single copy, but if present in homozygosis, they can lead to severe clinical outcomes. Often, couples carrying unidentified genetic mutations become aware of their dangerous mutations only after conception of an affected child.