Children are inferior good because they drain the hard earned resources of nearly all around them. They serve no practical purpose whatsoever. They smell horribly and spread dangerous, often deadly diseases. They will only exacerbate the nearly unavoidable ecological and economic crises we face as a species and a planet.
Children are inferior goods because they soak up the hard earned money of their parents, who probably did not what them in the first place. Additionally, they have no practical or monetary value whatsoever. They smell and are vectors for harmful diseases. They are just a continuation of an ongoing population crisis and must be eliminated sooner rather than later.
Children are not "goods" at all. They are people. Immature people, yes, but they will grow into productive adults (at least, most of them will). "Goods" implies property, not humanity - unless you want to take the slaver's perspective. But even from their viewpoint, children had various benefits that adults didn't always have - for example, children can be trained by their owners to behave to specific guidelines. But I think that's a little outdated, don't you?
NO, children are not inferior goods! That would mean that adults would be considered inferior goods, as well! Just because children don't have the ability to function in society doesn't mean that they have no value. All of us start off as children in this world, and gain the skills and abilities to be a productive part of the world as we live.