Your answer is #4. All of the above.
1. genetics is part of our DNA and that's how genetic mutations and such are tested is via DNA.
2. Genetic testing can help diagnose diseases. Think of a fetus in utero. They do genetic testing on the mother to see what the possible outcome of their genetic make up will be and the probability of having a genetic abnormality.
3. Genetic engineering may some day be able to prevent disease because if you look at the new science, they've already been able to create "fashion babies" that (in my opinion, is ethically immoral in the medical scopes); they can physically alter the DNA of an embryo to make the baby have blue eyes, blonde hair, etc....So, by way of process of elimination, they're clearly trying to come up with how to prevent genetic mutations and abnormalities before birth.
