Your deck rails need to be low enough and your vertical rails spaced so a young toddler can't roll under and out or stick his head in or body through. Don't know if that's code, it's MHO and if there are no toddlers in your life now, somehow, someway, they'll show up. Because a neighbor has a toddle we keep our pool gate "toddler-proof". My cleaning lady had to bring her toddler to work here one day.