  Early on the in the HGP, it was recognized that the development of genetic tests would precede, perhaps by decades, the capacity to treat the corresponding conditions successfully: this emphasized the importance of confronting the ethical implications of genetic testing. Genetic testing is carried out for a range of purposes: diagnostic, predictive, and reproductive. Diagnostic genetic testing is performed on individuals already experiencing signs and symptoms of disease. Predictive genetic testing is performed on individuals who are at risk for inheriting a familial condition but do not yet show any signs or symptoms. Predictive testing is presently offered for a number of conditions: these include Huntington's disease (HD), cystic fibrosis (CF), sickle cell anemia, breast cancer, and colon cancer. Although the HGP was defended by its proponents on the basis that the knowledge of individual genome sequences would facilitate the movement from a reactive to predictive medicine, there are no cures yet for most diseases identified as having a genetic basis. For some conditions, like familial hypercholesterolemia or polycystic kidney disease, early intervention may lessen the severity of symptoms. Reproductive genetic testing is carried out in several ways: through carrier screening, prenatal testing of the fetus in utero, and preimplantation genetic diagnosis (PGD) of embryos created by in vitro fertilization (IVF). In carrier screening, prospective parents find out whether they are at risk for passing on disease-related genes to their offspring. Prenatal genetic testing of fetuses in utero is conducted through the use of blood tests early in a woman's pregnancy, chorionic villus sampling (CVS) at 10–12 weeks, and amniocentesis at 15–18 weeks. Testing is generally offered to women for whom risk is elevated because of age or family history; based on the results, women can elect to continue the pregnancy or abort the  fetus.[43] In PGD, a single cell is removed from the 8-cell embryo for testing; based on the results, a decision is made about which embryo(s) to implant in the woman's uterus. In the U.S., PGD is restricted to private clinics because of the government's ban on the use of federal funds for embryo  research.[44]