It's only allowed if your conscience allows it! They did make that Hatred game where you go on a killing spree..so..anything goes. There's also zombie kids in Dying Light..pretty creepy...and that newborn zombie from Dawn of the Dead..and examples can go on and on.
Replies
https://www.google.cz/search?q=dying+light+baby+zombie&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjQ0avrtejKAhWIChoKHUJjCwQQ_AUIBygB&biw=973&bih=882