Question

Why do some people have moustaches and some dont ?​

Answer 1

Answer:

Low testosterone levels. In some cases, low testosterone may be the cause of poor beard growth. People with extremely low levels of testosterone have next to no facial hair. Unless your testosterone levels are clinically low, they probably aren't impacting your facial hair growth.

Answer 2

Answer:

That's true. Not all can grow beard.

People can have facial hair in different density. Some have very soft hair (women, kids, teenagers) while some have thick and dense hair, while many don't have anything at all.

It all depends in genome and harmones of an individual.