Having kids affects your bottom line at first. Later on in life, it's YOU will will be costing THEM. Social Security for example; when your kids get jobs and pay into SS, that's the money that will be in your SS check.
I've got my two sons, both cost me big time in college tuitions all the way back to the birthing hospital bills, but I am convinced it's an investment for my old age quality of life. Getting old is tough. Getting old and all alone is, for me anyway, unbearable. My quality of life is far better with the kids and now grand kids than it ever would have been as a life without 'em.
What good is a better bottom line if there's no one in your life to enjoy it with?