CVS and amniocentesis are two invasive techniques that can be utilized to rule out, definitively, Down Syndrome and other genetic diseases. Down Syndrome is an age-related that has a incidence of about 1/250 at age 35; and 1/100 in age 40. If people over 35 want to do a definitive test, they can do either of these two; depending on if they want to do it early, at 11 or 13 weeks with a CVS, or more in the range of 16 or 18 weeks with an amniocentesis. Amnio is done later, but it's a little safer and a little more accurate. In an increasing number, in today's world, we are doing screens of the nuchal translucency and screens in the mom, to calculate out people's risk. In the state of California, this is called The Nuchal Translucency Program. For people of all ages, people can do this to calculate out their risk, and determine if amniocentesis or CVS makes sense.