The doctor you are quoting is wrong. Actually, there are many studies which show a significant bra-cancer link. I suggest you see this article on Goop, written by the personal doctor to Gwenyth Paltrow. http://goop.com/could-there...

The fact is that bra-free women have about the same incidence of breast cancer as men, while the tighter and longer the bra is worn the higher the incidence rises, to over 100 times higher for a 24/7 bra user compared to bra-free. Sleeping in a bra is the worst thing you can do for your breasts.

Bras also cause droop, as shown by research. The external support from the bra causes the natural suspensory ligaments in the breasts to weaken and atrophy. Getting rid of the bra results in the breasts lifting and toning.

If your bra leaves red marks or indentations in your skin then it is too tight. I suggest women try going bra-free for one month to see how their breasts feel. If you feel better without a bra after that time, then your bra has been harming your breasts.