The real Morrow is not able to realise his potential since he was crippled in an accident, and therefore needs Vincent as much as Vincent needs him. The scientific premise, like in most science-fiction movies, combines a mix of truth and fiction. In the movie, the alleles from parents are so chosen that the combination produces the optimal arrangement in terms of the child's genotype. For more complex behavioural traits such as intelligence, aptitude test results would be a far better indicator than genetic makeup. Information, of any sort, is a valuable commodity in this day and age, and the kind encoded in DNA is no exception.
Humans naturally use information to discriminate.
I would argue that for some of scenarios posited in Gattaca , the genetic information is far less reliable than physiological and psychological histories. The acting by all the characters is quite good, though Jude Law as the real Jerome Morrow manages to steal the show. The narrative style at the beginning of the movie I thought was far more interesting than the actual sequences toward the end. Definitely worth watching on the big screen.