What Determines Breast Size?

Big breasts, little breasts, tear-shaped or round. Our breasts are as unique as we are and no one has the exact same pair. And for most of us, the breasts on our body aren’t even identical. One side may be smaller than the other, saggier than the other, unique in their own way.

So what determines breast size? Is it our mothers and the other women in our family aka genetics? Is it the foods we eat? Breast size is mainly determined by genetics but there are additional factors that may contribute to one’s breast size (and shape).


Genes affect every aspect of your body – your height, your hair color and breast size to name a few. In fact, genes are said to be the biggest contributing factor in the size and shape of your breasts. The way your breasts look and feel actually come from both sides of your family. So genes from your mom and genes from your dad contribute to your breast characteristics. If your mom is a C cup, there is a good chance you will be around a C cup but it is not guaranteed as there are so many other factors that may cause your breasts to be bigger or smaller.


Ethnicity can also be a contributing factor to breast size. Asian women generally have naturally small breasts (averaging a B cup) while Eastern European women generally have bigger breasts (averaging a D cup). Of course there are always exceptions as there are plenty of European women with naturally small breasts and Asian women with naturally bigger breasts.


Hormone levels during puberty can contribute to breast size. Breast growth takes a delicate balancing act of estrogen, progesterone, prolactin, testosterone and growth hormone. If this balance if off, it may lead to breasts not developing to their fullest potential.


Breasts are made of mostly fat tissue and for most people, their breasts fluctuate in size as they gain and lose weight. But for those who have dense breasts or more tissue and less fat tissue, they will not experience as much breast loss when they lose weight – lucky them!

Will Genetics Affect Breast Growth with Natural Breast Enlargement?

Genetics is said to play a big role in breast characteristics so does this mean if you and the women in your family have small breasts, there is no hope for you with Natural Breast Enlargement?

I personally do not think so. I think what matters most is finding the right program, being consistent and sticking it out until you reach your desired breast size. Chiyomilk, Mayusakimilk and a lady from Korea (A cup to E cup in 7 years!) are prime examples of this. Each one of these women started out with a B cup or smaller but after years of dedication with their breast enlargement program, they were able to grow a considerable amount.

Considering these women started out around a B cup and Asian women overall have smaller breasts, I highly doubt these women had naturally E or F cups in their family. So yes, I think you can grow past your family norm and even ethnic norm with once again – the right program, dedication and time.

For more factors that may affect breast size, read The Mystery of Natural Breast Enlargement.