considering reproduction be offered carrier screening before pregnancy if possible. Standard safeguards such as institutional review and demonstrated safety and effectiveness should be applied in initiating any carrier detection program. First, the test should be accurate, sensitive, and specific. In the future, such screening will be done increasingly as part of routine medical care; the same principles should apply regardless of the setting. Carrier testing and screening should also be voluntary, with high standards of informed consent and attention to telling individuals or couples, in easily understood terms, the medical and social choices available to them should they be found at risk for disease in their offspring, including termination of the pregnancy. Research is needed to develop innovative methods for providing carrier testing in young adults before pregnancy and to evaluate these methods through pilot studies. The committee had reservations about carrier screening programs in the high school setting in the United States and about carrier screening of persons younger than age 18.
With improving technology, carrier status for many different rare autosomal and X-linked recessive disorders will be detectable by multiplex technology (see Chapters 1 and 8). Obtaining appropriate informed consent before testing for each of these disorders will be a challenge (see Chapter 4). Multiplexed tests should, therefore, be grouped into categories of tests (and disorders) that raise similar issues and implications for informed consent and for genetic education and counseling (see Chapters 1, 4, and 8). If carrier status is detected, individuals should be informed of their carrier status to allow testing and counseling to be offered to their partners. Usually, the partner will be found not to be a carrier; however, if both partners are carriers, they should be referred for genetic counseling to help them understand available reproductive options, including the possibility of abortion of an affected fetus identified through prenatal diagnosis.
Anyone considering prenatal diagnosis must be fully informed about the risks and benefits of both the testing procedure and the possible outcomes, as well as alternative options that might be available. Disclosure should include full information concerning the spectrum of severity of the genetic disorders for which prenatal diagnosis is being offered (e.g., cystic fibrosis or fragile X). Furthermore, invasive prenatal diagnosis is only justified if the diagnostic procedures are accurate, sensitive, and specific for the disorder(s) for which prenatal diagnosis is being offered. Standards of care for prenatal screening and diagnosis should also include education and counseling before and after the test, either directly or by referral, and ongoing counseling should also be available following termination of pregnancies.
The committee believes that offering prenatal diagnosis is an appropriate standard of care in circumstances associated with increased risk of carrying a fetus with a diagnosable genetic disorder, including the increased risks associated