I do not understand why I am flatchested. My mother is far from being flat so why havent these genes been passed down to me. Even my little sister is way bigger than me. I'M 17 almost 18 so I'm pretty much done with any developments. It's not like im skinny or anything, I'm actually kind of curvy except up top. Maybe I have a lack of nutrients in my body. What kind of vitamins should someone take to make sure a person is getting proper nutrients through out the body?
your parents can pass on genes which they have but which are not expressed which have come from generations further back. You n=might still have some growing to do. there isnt really a set time in which people have to stop grwoing. it tends to be around eighteen but it varies with everyone. My auntie was five foot five when she was eighten and by the time she had turned twenty two she was six foot three. Theres really no such thing as normal!
..and don't forget the father's family - which obviously has had women in it. You are the product of genes on both sides of the family.
(It also works the other way - all my mother's line were, if not flat-chested at least small-breasted - me too. But my daughter is not. On the other hand, her father's mother and sister are both quite buxom.)