All in all, every parent and every child is/are different.
I know that subjects with 'every' count as singular, so in case I wanted to say 'Every parent is different', then I would have had to use 'is'. But this case makes me wonder, whether the subject is plural or singular, since it's 'every parent and every child'. I suppose it's the 'and' that confuses me.
Could someone please explain which is correct and why?