In GATTACA, what is the main method of genetic engineering used?

The main method of genetic engineering depicted in GATTACA is pre-implantation genetic diagnosis (PGD). In the film's society, individuals are conceived through in vitro fertilization (IVF), and their genetic material is screened before implantation to select embryos with desirable traits, such as intelligence or athleticism. This process exemplifies how genetic engineering is portrayed as a means of designing offspring to meet specific societal standards.

PGD allows parents to make decisions about the genetic traits of their future children, emphasizing themes of eugenics and the ethical implications of such choices. The characters in GATTACA live in a world where one's genetic makeup largely determines their social status and opportunities, reflecting the film's exploration of genetics and identity.

Other methods like gene editing and CRISPR technology, while prominent in modern discussions of genetic engineering, are not the specific focus within the context of the film's plot. Similarly, somatic cell nuclear transfer relates more to cloning and is not the method employed for genetic selection in GATTACA's narrative.