I saw a movie several years ago and I have not been able to find it since.
It was about a dystopian society where parents could modify the genes of their children before birth.
Some individuals, including the protagonist, had not had this done, and so had a somewhat inferior genetic makeup.
Jobs are based on the results of genetic tests, and the protagonist, a male, was slated for a less than ideal job. In the movie, he fakes his identity and has major surgery to make him a little taller to match his ID. He is trying to get his dream job (astronaut?).
The only other parts I remember are
the protagonist, to keep up the ruse, managing to run on a treadmill faster than his genetic limit
a very suspicious character pulling the protagonist's DNA from a hair left in a comb