In the case of genetic or chemical predisposition to any imperfection, we cannot (short of miraculous intervention), stop the disposition, because our chemistry is not really under our willful control. However, our will may be developed stronger than our imperfections. The imperfection is controlled, rather it controlling us. The saints have conquered every sort and degree of imperfection, and so can we. As the body of Christ, we need not rely only on our mere human strength, we have the entirety of Christ to help us.