The title is based entirely on the initial letters of the four DNA nitrogenous bases (guanine, cytosine, thymine, and adenine). During the credits the letters G, C, T, and A are all highlighted in blue font. While the movie title "GATTACA" uses the 4 DNA nucleotide abbreviations of G,A,T,C, more specifically, when identifying genetic markers, the tests measure "short tandem repeats" at specific DNA marker locations. These are known as "GATA or CA" repeats - hence GATTACA.
Jude Law's character asks to be called by his middle name, Eugene. "Eugene" comes from the Greek for "well born," which Jerome is. "Eugenics" (the science of improving the hereditary qualities of a race or breed) is the central theme of the film.