Kids consume more energy pound for pound than adults with regards to food. There’s also all the associated products that go along with raising children, many of which aren’t handed down, etc.
Kids do have a lot fewer pounds though. Also humans live around seventy to eighty years. So stopping procreation right now would bring us to carbon neutrality in about that time. That means that in about twenty years stopping procreation would have reduced carbon emissions by about thirty percent or so. That's a lot, but far from what's needed to prevent catastrophic warming.
