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Why Do I Have Small Boobs? 4 Reasons Why You Are Flat-chested

In this post, I will let you know the reasons why I am flat-chested, why some women have small boobs and why it’s completely normal to be that way.


I’m flat-chested. My chest is as flat as an ironing board and I love it. My bra size is 32AA and I actually have stopped wearing bras for the past 2 years because even when I don’t wear them, my nipples still don’t show through the fabric, so what’s the point right? :)


There are four main reasons why girls like me and a lot of women have small breasts.


Click ▶️ to watch the video version of this post


1. Genetics


The first and most prominent reason for having a flat chest is your genetics and family history.


Genetics plays the biggest role in determining the size and shape of your breasts. Your genes influence the levels of your hormones, which affect your breast tissue.


Genetics affect breast size

Genes also determine how dense your breasts are, as well as what your skin is like, which affects the appearance of your breasts.


A study in the journal BMC Medical Genetics analyzed data from over 16,000 women and found a total of seven genetic factors were significantly associated with breast size.


Your breast characteristics can come from both sides of your family, so genes from your dad's side can also affect what your breasts end up looking like.


If your mother, sister and aunts have small breasts, it’s not a guarantee that you will also, but you’re more likely compared to other girls who come from a family of women with bigger breasts.


So I don’t really know how my mom’s breasts look like (she passed away when I was 4), but I heard that she's very petite, she’s 4’9 and she’s not well-endowed either. So I guess I just inherited that from her and now I look the way I do because of her. Thank you Mom! ILY!


2. Your race and where you're from


Secondly, your race and where you are from may play a role in determining your breast size. In Asia, the average breast size is an A cup, while in the US, the average breast size is an F cup. Where I live right now in Canada, the average size is an E cup. So as you can see, there’s a huge variation in the breast size of women depending on the country or region that you’re from. If you’re Asian like me and you have a slender figure and small chest, just know that it’s completely normal to have A cup, AA cup, or even AAA cup.


A recent and most complete study from the Female Journal of Health Science lists the result of a very conclusive study. In more than 100 countries, women's bodies were measured using mostly 3D body scanners. In the evaluations, there are no self-assessments, but only the results of medical professionals. All subjects were between 28 and 30 years old and were divided according to their country of birth. All women were in normal health, not pregnant, not lactating, or hormonally treated and had no breast surgery.


The study analysis revealed that there is considerable variation in the breast size of women depending on their country of birth. For example, women born in the U.S have by far larger breasts than women in any other country, while women born in Africa and Asia, especially in East Asia, have the smallest breast size. Looking at this map does make me feel slightly better knowing that I fall right into the average size of where I am from.



Ranking of breast sizes around the world

But of course, take this with a grain of salt because our bodies are all different and there are so many factors that affect the growth and size of your breasts, so if you’re from a country where being busty and curvy is the norm, just know that there is nothing wrong with you, there’s nothing wrong with being naturally skinny and small-chested. I know that it may be really hard for you when you don’t fit into the cultural norm, but trust me, being different is oftentimes a blessing, not a curse. Being different from other people makes you special, not abnormal. Being different may make it so hard to love yourself at first, but once you learn to embrace what makes you unique, the love that you have for yourself will be so profound and deep that makes it all worth it.


If you’re from a country where being busty and curvy is the norm, just know that there is nothing wrong with you, there’s nothing wrong with being naturally skinny and small-chested.

3. Weight


The third reason why you are small-chested is your weight. If you’re skinny or have low body fat percentage, you’re likely to have smaller breasts compared to heavier girls. Thinner women usually have smaller breasts, and vice-versa. The stage of development in puberty can also play a role, but that factor is also connected to body shape and size: again, thinner girls tend to start growing breasts slower or even later than average.

Thinner women usually have smaller breasts, and vice-versa.
weight affects breast size - why am i flat chested

No matter how big or small your breasts are to begin with, a large proportion of the breast tissue is made up of fat. So it's no coincidence that your breasts expand when you do. Similarly, when you lose weight, your breast size could change too. How much fat you lose in your breasts when you drop weight may depend on the composition of your breasts.



4. Exercise


Lastly, your breast size may also depend on the type of exercise you do and how physically active you are. Have you ever seen a ballet dancer or a swimmer with big breasts? The more intensively and frequently you exercise, the more likely that your breasts will be on the smaller size of the spectrum.


The reason for that is because exercise at high frequency helps you reach a caloric deficit. Over time, using more calories than you eat forces your body to use its fat stores, including those in the breasts.



exercise make breast smaller


Also, lifting weights, doing push-ups and other pectoral exercises can also make your breasts look flatter because you turn tissue into muscle.


Doing a lot of exercises can flatten the supportive and fatty tissues of the breasts, but regular and normal amounts of exercise can actually make your breasts look fuller, lift a certain part of the fatty tissue and turn it into muscle.


ALL breast sizes are beautiful and we should all embrace what makes us unique.

I hope that this post helps you understand why you have the breast size that you have! I strongly believe that ALL breast sizes are beautiful and we should all embrace what makes us unique. We are all created perfectly and we look the way we do for a reason. God created us with the body that’s uniquely ours and perfect for us, and our job is to love our body as much as possible: all parts of it, breasts included. I hope that one day in the near future, you will finally love your small breasts, celebrate them and proudly show them to the world. If you’re on a journey to learn to love yourself, just know that you have my full support and I’m here for you every step of the way.


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