I'm just sayin'. Maybe not specifically about breasts if you're not a boob guy, but in general, while being able to have control over your sexual desires and urges is realistic, being able to simply not have any?
At will? That's another thing all together.
I'm aware some people are actually "asexual" to some degree or another, but I'm of the suspicion that they're far fewer and far between than some would have you believe.