While the tests 23andMe and other companies like them offer an overall snapshot of your future disease risk, much of what those screenings look for in the genetic code is not well known yet. The 23andMe test looks at only small segments of the DNA, called SNPs, and the test is limited to looking at less than a million SNPs (whereas the human genome has around 10 billion SNPs identified so far). To have your entire genome decoded would cost around $3,000 with current technology. The 23andMe test is different from looking at a specific gene, like BRCA1 or the gene that causes HD. It is important to know the differences between various types of genetic screenings, and understand the implications of the results.