This could actually be a plot point on a dystopian sci-fi movie (identifying people by weird metrics like toe size and such)
Although in the future I imagine it's more likely to be things like arm to torso ratio or gait recognition or similar, done via machine vision.
Biometric comparison is commonplace, once you give your biometric info
What I'm saying is that people would be id'd by a biometric measure derived from a genetic measure
(and yes of course I watched Gattaca already)
what this thread is about is denying a kid a kindergarten spot because the dna shows their height will never get them a basketball college scholarship.
And people are made to care about things that don't actually make any sense all the time, you just gotta set up the incentives just right.