Before understanding baldness, it is important to understand what is ‘Normal and Healthy’ hair. Each individual hair strand goes through a cycle of 3 stages:
1. Hair Growth
2. Fall
3. Replacement

The normal growth rate of a scalp hair is 0.3 to 0.4mm per day and around 1cm per month. A certain amount of hair is shed daily, thus making room for a new hair, the average hair shed per day is anywhere between 75 to 100 hairs.
Hair is replaced whenever it is shed, hair grows rapidly between 15 to 30 years of age and gradually declines. If the hair loss is beyond the estimated average hair shedding and if the sheded hairs are not replaced by new ones, it can lead to baldness.

It is a myth that baldness occurs in males only, It very much occurs in females as well, however the rate is comparatively slower to the males.