Re genes- do you really not get it, or are you just pretending? I and others here have repeatedly given you examples of genetic diseases that are present throughout the world, several of which have increased in frequency of diagnosis as the population has aged and/or had children later in their lives. Downs Syndrome for one. In many cases these are de novo mutations- they don't need to spread. But for your broader enlightenment, I will point out that you are correct:
human genes generally don't swim. Instead they take airplanes, ships, trains, and cars (think about it if you don't understand that statement right away).
As to the "survey." The huge flaws in self-reporting, especially from biased populations, have already been described to you in your other thread. Here is one general discussion:
http://en.wikipedia.org/wiki/Self-report_study.