Not to say this as an attack against you, just that from my perspective it absolutely should be a legitimate movement, not just a private belief. The reasons I believe that are several: I believe that as a society, we really don't think critically about following the conventional path as much as we should.

There is a serious overpopulation issue in the world which is causing a drain on natural resources, particularly non-renewable ones. This is especially true in poor and unstable nations.

There is a macro economic issue: Who is going to employ all of these extra people, in a world where jobs are increasingly being mechanized? Are we creating a whole generation of people who will end up out of work and on welfare?

There are financial consequences to families having more kids than they can afford (even 1, for people who are very poor), leading to long term poverty, and potentially resorting to crime to make ends meet.

There are, especially important, social harms that are committed by bad, abusive, and neglectful parents; parents whom society would be better off if they chose not to have kids. ["Chose" is the key word here. I'm not advocating sterilization or anything crazy like that!]

And then there are a lot of people who simply don't really want kids, but they have them anyway because of societal pressure. This type of pressure is sexist (it disproportionately burdens women), overbearing, and irresponsible, and it needs to stop: Think about it, if a person isn't absolutely ready and willing to have kids, they probably aren't ready for the responsibilities of parenthood, are they? And what about the interests of the children--don't kids deserve parents who are very loving and happy, rather than parents who are distant or resentful because they weren't able to pursue their own dreams?

Sorry for the long rant, but I think if people thought a little more about the consequences of reproducing without careful thought and long term planning, we would all be better off.