What is the term for testing an embryo for genetic abnormalities before implantation?

• A. In situ hybridization
• B. Amniocentesis
• C. Karyotyping
• D. Preimplantation genetic diagnosis

Answer: (D)

Preimplantation genetic diagnosis refers to the process of testing embryos for genetic abnormalities prior to implantation during in vitro fertilization (IVF). This technique allows for the identification of specific genetic conditions or chromosomal abnormalities before the embryo is transferred to the uterus, helping to ensure that only genetically healthy embryos are selected for implantation.

This is particularly beneficial for couples with a known risk of genetic disorders, as it aids in increasing the chances of a successful pregnancy and a healthy baby. By conducting genetic analysis on the embryo at this early stage, it provides valuable information about the embryo's genetic health, allowing for informed decisions about which embryos to implant.

The other options mentioned do not fit this description. In situ hybridization is a technique used to locate specific nucleic acid sequences within fixed tissues or cells. Amniocentesis is a procedure conducted during pregnancy to obtain amniotic fluid for genetic testing of the fetus, and karyotyping is a method used to examine an organism's complete set of chromosomes, typically performed on cells collected after conception.