Re: Hereditary Small Breasts

I came across this, which relates to your question:

"You may be small breasted because of a genetic trait, but that is only one possibility as there are many reasons why a woman may have small breasts. In puberty her hormones may not have been released in the right quantities at the right time, for which there could be many possible causes quite unrelated to genetics. Breast growth is essentially a reaction to hormonal stimulus and not generally a condition that is locked into some genetic code. Admittedly, genetics could still be the explanation in some cases, and maybe it is in yours, but in reality it's low on the list of possibilities and is not likely to be a common explanation for lack of breast growth."