Book excerpt: Why does my sister's DNA make it look like she has different ancestors from me? How reliable is that paternity test? What about the one that is supposed to tell me whether my brother and I share one or two parents? If a DNA test says you and I are first cousins, is that all we could be? Dr. Starr answers these and many other questions by explaining the science behind the tests in a simple and entertaining way and then by going through what the tests can and can't tell you about yourself and your relatives using plenty of real stories. If you are thinking of getting a DNA test that looks at relationships or ancestry, this book can help you decide which test to take and then help you interpret the result.