Because a child signals are potentially easier to understand, due to the parent and the child being from the same species. Kind of funny, we did make a similar

Because a child signals are potentially easier to understand, due to the parent and the child being from the same species. Kind of funny, we did make a similar choice (although only in terms of which one first. We wanted children) and the feeling of being incompetent dog owners was one of the reasons pro "no dog"