Well, it could be a personal opinion, but kids are an inspiration to lead a major part of our life - to upbring and enable them and make them better human becomes our duty, a core value that probably fulfills a large part of our purpose of life. I understand some people don't want to take responsibilities having their own reservation on this subject, but I have seen both examples and people who do not prefer to have kids, regret later in life, unless they become a monk.