How to reduce boobs size

Surgery?

Why are you asking, rather than your wife? Is she uncomfortable with the size of her breasts?

Surgery is the normal route used to reduce the size of breasts, but if she is overweight, she might also consider dieting. Your health insurance won't cover breast reduction surgery unless the reduction is medically necessary - if, for instance, she's having trouble with neck, back, and shoulder pain that is medically proven to be caused by her breast size.

Exercise will reduce their size. Sometimes dramatically, sometimes not so much. If your wife is uncomfortable with her size she can lose weight and usually the breasts are the first to go. Other than that, surgery is really the only option. Breast tissue is mostly fatty so if you are to rid your body of as much fat as possible, they will naturally shrink.