In order to understand the various genetic causative factors in Infertility, Fetal wastage, congenital malformation, single gene disorder in the off spring as well as history of chromosomally abnormal individual in the family /anomaly in the family, chromosomal variation, effect of consanguinity, malignancy it is important to understand the mechanism of transmission of genes to its progeny.

The present atlas is towards an effort to put forward the above facts in a simple theoretical and pictorial form. With the extensive use of ultrasound, it has also become possible to correlate the sonography marker as soft marker to strong marker for chromosomal disorder which is included in the atlas. Majority of the prenatal cytogenetic study today is for a likely chromosomal defect in the fetus. The confirmation of the fetal chromosome becomes necessary because of the nature of irreversible action it can follow.