My son is 2 years and 4 months old. He is very smart. Lately, he began biting his nails, so his nails are always short. I do not know whether he swallows the cut nails or not, but I rarely see the remainings. Should I try to stop him or not? If yes, how to do that?
Pros: While biting his nails, there may be some dust, germs, bacteria, virus, etc. It is scary if you see what is under or inside his nails. Science tells, nothing to worry about while biting it, though some portions of those stuff is going inside his stomach. It can cause few health problems initially like diarrhoea, dysentery etc. Still, it is helpful for his later life as it produces antibodies which prevents him in future. Once antibodies are produced it becomes a safeguard for that reason.
Cons: Problem or worrying matter is if it becomes his regular habit. Changing habit takes time. I heard some of my friends tell that their child even eats nails of the foot. If it becomes a bad habit, it needs to change. For your child you can try to divert him from doing this or tell some story where the end of the story is diseases caused by eating/biting nails.
My suggestion is if it is not in severe stage that it become bad habit you can just warn him not to do so. Sometimes after certain age child leave it. On the other hand if he is serious about nail biting try to divert him. When he starts it in front of you, immediately say something else or start some game with him or say, "Let's run from this room to that room. Let's play..."