So would you allow five year olds to vote? You have to have an age requirement somewhere.
The problem with rules around voting is that they can always be exploited. I generally believe that the best way to avoid that is simply to remove rules aside from 1 person 1 vote.
Interacts badly with mail in and lots of other issues of course.
What you're proposing is nothing but an absurd over-representation for parents of small children, who will be able to vote twice or even more.