It depends on the creationists, but generally even the staunchest creationists recognize the efficacy of modern medicine and science. Some incredibly fierce creationists are scientists (not many, but they're around), and the demonstrable scientific studies and methods are far easier to convince people of than the more esoteric concepts that challenge beliefs.
Yes, I believe that creationists believe in human genetic science like mapping chromosomes, because you do not have to reject science in order to believe in creationism. We all agree on the science of what exists today. It is reasonable to still have doubts as to whether God allowed evolution or if he created animals perfect. Either way, science is still a valid study.
Since Creationism doesn't have a lot of scientific support and is based in a literal reading of the Bible, I don't think Creationists would believe in genetic science. They don't believe in evolution, which does have scientific support. Human genetic science would likely force them to confront evolutionary science, which would seem in opposition to their beliefs.
Creationists do not accept science almost completely. Most discount any scientific knowledge unless it can be backed somehow in scripture. Even that is a touchy subject. The general idea would be that genetic mapping leads to genetic manipulation which is actually playing God. Humans should not toil with God's work. If a child is born with a disfigurement or disease, that is God's will. Trying to map out his plan and manipulate it is blasphemy.
In general, creationists believe God created man in His own image and has remained unchanged since then. That's not to say all creationists disbelieve in genetic theory and mapping chromosomes. Everyone on this planet, to some degree, has to rely on logic and science simply to survive contemporary times. I would say creationists usually believe man is designed solely around God's plan.