Wow, @papa-pepper, you have something unusual growing in your garden. This doesn't happen a lot but it can happen in seeds that we save from our own harvests (Not GMO). It can be caused by defects in the chlorophyll synthesis to how the chloroplasts divide during growth. It is awesome to see them grow and they may grow long enough to provide some educational opportunities for the kids but in most cases, they will die before maturity.

So when you see white plants growing in a batch you plant from seeds that should all come from the same inbred line, (meaning you didn't purposely crossbreed) it is a pretty good indication these seeds are carrying a genetic mutation in its recent history.

So in a nutshell, it is not harmful to you, but it is fatal for the white corn plants.