My two teen boys (15, 17) constantly chew their fingernails. They can't go a minute without sticking their fingers int heir mouths. Should I care? They don't even know they are doing it and often bite their nails in public or in large groups. The nails and cuticles on my youngest son's fingers look like hamburger. I find it gross and constantly scold them for chewing. I'm pretty sure that's not a good idea, but it really bugs me to no end.
How can I put an end to this?