My girlfriend is 120 with size D, 5' 4" or so

She can stand fine, since she is young, but later in life, it will most likely takes its toll on her back.

And she complains that while she runs, her boobs are a royal nuisance. After a mile or so, they hurt, and from watching her, I can see why.

If she were to have breast reduction, she could run with me, spar with me, etc without hindrance or inconveniance or pains because of two large deposits of fat.

I just can't grasp how one would think that breast reduction is stupid, seeing as the cases of post-operative growth are minute and that it's freeing the woman to feel better about herself and perform more activities without hindrance.

I like big boobs, but I don't like seeing her struggle with things, or not being able to do things, just because she has large boobs.