Why are breasts different sizes?

During puberty, breasts don't always receive identical amounts of the hormone that makes them grow. Why does this happen, and how common is perfect symmetry anyway?

Knowing your boob shape will get you one step closer to bra heaven

Is It Normal To Have Different-Sized Boobs?

How Prophylactic Mastectomies Work

Does Breast Size Matter? La Leche League Canada - Breastfeeding Support and Information

What Causes Uneven Breasts and How Can You Fix Them?

Asymmetry of the chest: what to do if the breasts are of different sizes. How to fix breast asymmetry

Breast Asymmetry: Causes and Diagnosis

Why Is One Breast Bigger Than the Other?

My boobs are different sizes - it's affected my whole life here's the worst part

How to Measure Your Bra Size: Bra Size Charts, Band and Cup Measurement Guide