ABSTRACT
According to a generally agreed definition, infertility is the inability to have off-spring despite active sexual intercourse of a couple for at least one year. Pre-implantation genetic testing as an alternative to prenatal diagnosis was introduced over 30 years ago. Nowadays FISH on human sperm is most commonly used to determine the proportion of aneuploidy present in autosomes and sex chromosomes of infertile men. As sperms are extremely condensed, being caused by extensive intermolecular disulfide cross-links, they must be decondensed prior to the FISH procedure. Interpretation of abnormal findings from FISH sperm analysis can be evaluated using the quantitative or the qualitative approach. Shortcomings of FISH sperm analysis are the inability to access structural chromosomal aberrations and the fact that sub-regions of chromosomes are studied, as locus-specific probes are normally used. Reasons for signal loss may be too short denaturation or hybridization time.
