The growth of foetus/ embryo is quite fast compared to the early days after birth. The individual registers a regular growth after birth upto the age of six or seven years. Thereafter there is a sudden spurt in growth for about three years. There are different ways adopted to study the growth patterns which have certain parameters such as age, sex and other environmental conditions. This we will be discussing in the next chapter. The velocity curve of growth in height begins a considerable time before birth. Most skeletal and muscular dimensions follow approximately the growth curve described for height. So also do the dimensions of organs such as liver, spleen, and kidneys. However there are other tissues which have curves sufficiently different. These are the brain and the skull, the reproductive organs, the lymphoid tissue and the subcutaneous fat. Growth also shows sex differences over a period of time.