genetic inheritance or hormones effect?

Question

im the only one in my family to have chest hair(not hairy,just tiny but dense and still growing).my brothers doent have it,so as my father n my grandfather.im just 19 years old.
one more thing,why i still cant grow beard?
girls in my class like it.looks sexy and mature..

Answer 1

First, your body hair appears to be developing ahead of your beard. Sounds normal to me.

Genetics? Remember that you have two grandfathers, one from your mother's side too. Are the males on your mother's side hairy? Just because your dad gave you your Y chromosome (which made you a male) that doesn't mean every single male sex characteristic you have came from your father's side. There may be hairy guys on your mother's side.

Why isn't your brother like that? Even though you have the same mother and father, you actually have different amounts of genes from each of your four grandparents. (Other than body and facial hair, there are other differences between you two, isn't there?) A lot of this has to do with the biological term used in genetics called "crossing over." That's when either your mother's egg's chromosomes or your father's sperm's chromosomes started exchanging genetic material with each other -- in their bodies -- long before those two ever got together and had sexual intercourse to produce you. There was a mixing going on right then and there of each of their 4 grandparents genetic material. Sort of confusing, isn't it? Yet, in the same way, beautiful. That's why we have such variation between brothers and sisters.

You are hairy because somewhere way back, you had a hairy male ancestor, and now this right combination of genes from your four grandparents makes it easier for those genes to express themselves. My guess is that somewhere along the line, both your mother and dad had a hairy male ancestor.