Activity 2.1.1 Chronicles of a Genetic Counselor INTRODUCTION Both of the Smith brothers are faced with difficult questions regarding the health of their future offspring. James and his wife will soon be having a new baby. Aaron and his wife are hoping to become parents. Tests that screen for abnormalities in the genes can provide information about their children before they are conceived or before they are born. They both hope that a genetic counselor can offer advice and help them navigate their reproductive choices. A genetic counselor can help a family understand the risks of having a child with a genetic disorder, the medical facts about an already diagnosed condition, and other information necessary for a person or a couple to make decisions suitable to their cultural, religious, and moral beliefs. Scientists have worked tirelessly to decode our genetic code. The goals of the Human Genome Project were to determine the sequence of the three billion base pairs that make up human DNA, identify all of the genes, and devise a method to store and analyze all of the data. The completion of this project in 2003 gave us the “parts list” for a human being. While scientists are still working to figure out how all of these parts fit together, they have learned the specific function of many genes in our genetic code, as well as how these genes determine traits and sometimes even signal disease. Our genome consists of over three billion base pairs. Surprisingly, less than one percent of these As, Cs, Gs, and Ts differ from person to person. Differences in our DNA help code for our unique appearance, personality, traits, and even our susceptibility to disease. Genetic diseases and disorders are illnesses that originate in our chromosomes and DNA. These genetic changes can be passed down from parent to child. Modern biology has given scientists the tools to examine changes in our DNA and to test for the presence of thousands of these genetic diseases. Genetic testing is the use of molecular methods to determine if someone has a genetic disorder, will develop one, or is a carrier of a genetic illness.