Can I break my lease because of mold?

I have contacted my apartment complex several times about this mold issue. Each time they come out they spray bleach on it. The mold seems to keep growing. This is now the 4th occurrence, and i have about 6 months left on my lease. I am itching to break it but i don't want to be penalized. I can not bear the smell of it anymore i have a 2 year old son, and found myself catching headaches frequently. I am very nervous about this problem. What do i need to do in this situation? Can i break my lease?Please advise.