By Dr. Ted

I got a private Facebook message today from a young teen concerned that one of her breasts was bigger than the other. She was wondering what she should do.

The short answer? I told her not to worry, to give it time. It’s not uncommon for breasts to develop unevenly during puberty, but by the time they stop growing they usually are more even. I also told her that there’s no such thing as perfectly identical breasts; most women have breasts that are slightly different sizes. It’s known as asymmetry.

The long answer: In puberty, breast development can start first on one side or on both sides at the same time. It takes about 3-5 years for the glandular tissue to fully develop and for breasts to reach their full adult size. On average, most women are finished growing by age 18, although some might continue to grow into their early 20s.

That’s about the time that the majority of women come into my office to find out about cosmetic breast surgery. They are still under the impression that breasts are supposed to be identical. Actress Jennifer Lawrence (star of The Hunger Games) made headlines earlier this year when she told Jimmy Kimmel that her breasts were uneven.

As one of my staff members said when she was interviewed for our recently released book, The Scoop on Breasts: A Plastic Surgeon Busts the Myths, “Before I started to work here, I had seen very few breasts. I didn’t have any sisters. We didn’t get undressed in front of each other in gym class; we didn’t talk about our breasts or look at each other’s. I think this is the case for most women.”

Time after time, when a woman comes in for a consultation and looks at dozens of before and after photos, she is relieved to find out that she isn’t the only one with breasts of different sizes.

Few women have identical breasts: Breasts are sisters, not twins. The difference might be slight or more obvious. Chances are one of their feet is slightly larger than the other one, too. That’s because the two sides of the body are not perfectly matched mirror images. They are asymmetrical.

Nipple position, chest diameter, the amount of breast tissue, and the location of the breast on the chest wall all contribute to the appearance of the breasts. When one breast hangs a little lower than the other, it might give the illusion of being bigger. It might also look bigger when there is a longer distance from the nipple to the inframammary fold (the crease beneath the breast). With all these variables, it is no surprise that no one has identical twins.

While some women are bothered by a size difference that’s as small as a few tablespoons, others don’t notice or don’t care. Some women address their concern by adding padding – or a “chicken cutlet” – to one cup of their bra; others opt to for cosmetic breast surgery.

If there’s a difference in the volume of the breasts, I can make them closer in size by enlarging them with breast implants of different sizes, augmenting the smaller breast, or reducing the bigger breast. I have operated on women whose breasts varied by as much as two-cup sizes, and I was able to make a significant improvement. You can see before and after photos here. While I cannot transform sisters into twins, I can make them look like sisters from the same family.