There could be many reasons both scientifically and theoretically.
I tend to not bother with the scientific facts too much.
So one of my favorite theories is this:
When you were a young baby, if your parents knew better they would gently stretch the skin around the testicle area each time they changed your diaper. If done correctly for several years, you will experience equal hanging. If done incorrectly, you experience the imbalance that you are experiencing now.