Prenatal and embryo screening are used to analyze the genetic make-up of a fetus or embryo, allowing decisions about whether to continue a particular pregnancy or use a particular embryo to initiate a pregnancy. Prenatal genetic testing came into wide use in the 1970s with ultrasound-guided amniocentesis. In 1990, embryo screening, also known as pre-implantation genetic diagnosis (PGD), was developed for use with in vitro fertilization (IVF) to determine whether an embryo with specific genes of interest should be used to initiate a pregnancy. Noninvasive prenatal testing (NIPT), which extracts and tests fetal DNA from maternal blood samples drawn as early as 8 weeks into a pregnancy, was introduced in 2011.
In principle, these tests can identify fetuses or embryos with any particular genetic sequence. Prenatal and embryo screenings and tests are used most commonly to identify Down syndrome and genetic conditions such as Tay-Sachs disease, sickle cell disease, thalassemia, and cystic fibrosis. They can also be used to select other gene-related traits, most commonly sex. Social sex selection raises concerns about exacerbating gender stereotypes and normalizing the “design” of children; in some countries, notably in South Asia and Eastern Europe, it has created dramatically lopsided sex ratios.
Many disability rights advocates, in particular, have been critical of genetic selection techniques. They typically support women’s right to decide whether or not to have a child at a given time, but are deeply concerned about basing this decision on the presumed traits of the particular embryo or fetus.