Wow, I thought the Living Earth Ethical Principle on family size was challenging--since it encourages all families to give birth to just one child (though families should adopt as many additional children as they have the means and interest to raise). Then I learned today about the "Voluntary Human Extinction Movement." These are individuals who have not only agreed to stop reproducing but actually want the human species to go extinct (though not through violent means, just through choosing not to continue).
While I understand the impulse, really, once we can bring down the human population to a sustainable level--perhaps 1 billion with high-income lifestyles or 6 billion with middle-income lifestyles, then we can live in balance with the planet (though these estimates decrease each year we live beyond the biocapacity of the planet as ecological capital continues to be degraded or depleted). So while I find the movement thought provoking and funny, I hope people in the movement will consider a new focus: The Voluntary Human Reduction Movement, where members are encouraged to give birth to no more than one child per couple (with twins the accidental exception). That's a message that might resonate better, spread further, and still have significant benefits.