No , it is not taxable, as it does not fall within Income definition. At most it may be termed a Gift which is also not taxable.So, receive money from your son fearlessly , however if you are having income from other sources and filing return of income , it is better that you show this amount as tax free receipt in form of gift.

Also note that genuine gift was always tax free and now gift from relatives are made tax free expressly under the I T Act.