Genetics is the study of heredity and variations. Heredity and variations are controlled by genes—what they are, what they do, and how they work.
Heredity is a biological process where a parent passes certain genes onto their children or offspring. Every child inherits genes from both of their biological parents and these genes in turn express specific traits. Some of these traits may be physical for example hair and eye color and skin color etc. On the other hand some genes may also carry the risk of certain diseases and disorders that may pass on from parents to their offspring.
As per reports, chromosomal abnormalities occur in about 1 of 200 live births. Infants with these abnormalities have mental retardation and suffer from malformations and disabilities. Due to the large number of births (26 million per year), India has the largest number of babies born with chromosomal disorders in the world (1,30,000 per year).