Medically not all ailments are hereditary. When we mean genetic or hereditary; we mean the ability of a disease to be transferred to offsprings or generations of a parent. Sickness such as malaria, typhoid and headache cannot move from a parent to their offspring. But diseases such as cancer, diabetes, tuberculosis, shortsightedness, HIV/AIDS, leukemia, etc. can be inherited by the offsprings. This is because these diseases are caused by certain viruses that affects the blood and genes. Blood is life. Blood is what forms every human. These diseases are called genetic disorders. They are genetic problems caused by one or more abnormalities in the genome. There are some conditions in which genetic changes are responsible for.
Bad breath is not part of such conditions. Bad breath often results from negligence and nonchalance. The above question is like asking whether body odor is genetic or hereditary. The fact about our body is that if one refuses to keep the body in order, the body automatically produces an awful smell. This also goes with body odor, when you refuse to take your bath regularly and wear neat clothes, you stand a high chance of having body odor. Irrespective of the fact that either of your parent never had body odor. Same goes for bad breath.
Also an individual whose parents has dirty hair, is not likely to have dirty hair; because dirty hairs is not hereditary. It also results from negligence. Cleaning the body is a must. It is nonnegotiable. The body is meant to be cleaned at least twice a day. Not just cleaning the body, there are other accessories that can be used after washing the body; deodorants and perfumes helps maintain a neat body. A neat body is not also inherited; it is worked for. Just like when a individual is advised to cut down his/her intake of sugar and refuses to, over time such an individual may develop Diabetes. In such a scenario, developing diabetes is as a result of negligence.
Whether or not your parents had bad breath is not a determining factor for you having bad breath. Bad breath occurs when an individual neglects his/her responsibility towards the mouth. Bad breath also occurs when an individual consumes some certain things that are improper for the mouth. Things like cigarrete, alcohol, too much coffee is bad for the mouth.
In a nutshell, bad breath is neither genetic nor hereditary, when an individual fail to do what is right in terms of his body, this in turn affects his health.