I've always thought this kind of thinking was funny. When you boil it down humans are an object. We have a complex nervous system, but that doesn't make us not physical objects. I'm not saying this for any sort of political or social reason I just think it's funny. I mean I understand that human life has value to us because we are human, but I do find funny the metal gymnastics people go though to say we are something other then just complex chemistry. Having said that. . .JoJo said:"It" is reserved for objects rather than beings, you can probably get away with referring to an animal as it unless they are someone's pet, but don't be surprised if people are offended if you describe them or their kid as it, since you are effectively calling that person an object.
Yeah it's kind of not a good idea to call children an "it" Like I said human life has value because we are human. Saying it sounds like you're calling "it" not a human.