Let me introduce exhibition number one - the shakers [1]. At least they left us some nice furniture.

1. http://en.m.wikipedia.org/wiki/Shakers

There are other means of passing information between individuals in a population, e.g. by communication, upbringing, education, propaganda.

E.g.

Step 2. Extremely altruistic people cease reproduction and use the time and energy they would otherwise have spent on their own children to educate and encourage others to become more altruistic.

... and you wind up with those more predisposed to being altruistic, upon education and encouragement, also foregoing reproduction. The result may be a short term surge in altruistic behavior, but a stronger selection away from altruism at the genetic level.

In an evolutionary sense, altruism was valuable in tribes--having empathy meant helping people who shared a portion of your DNA, and was often much more beneficial than selfishness. Pretty obvious, really. Globalism has made it pathological, even suicidal. Genotypes related to generalized empathy--causing people to spend their resources, reproductive capacity, or their lives, helping unrelated people--are already doomed, even without suicide cults.

(The website is down, so I don't know what these people are trying to accomplish--I'm just taking the name literally.)

I was thinking almost the same thing: people choosing not to reproduce selects for those who will reproduce, making the effort ultimately futile.

But then consider what happens when sexual reproducing species experience an extreme population dip: traits suddenly become much more variegated because now there is an overlap of recessive genotypes that used to be hidden. So maybe this won't happen?

If one assumes that this kind of altruism is hereditery. I could just as easily be cultural.

I'm not so sure about extinction, but a steady state population (possibly with less people than now) seems pretty attractive to me. At the moment I don't believe we are culturally able to sustain this.

I often wonder what needs to be done to make it happen. Probably a more equitable distribution of wealth and resources is job number one (observing that rich societies have a low fertility rate). Which probably means that it will still be many generations before it can happen.

that's funny, because usually people are called selfish when they don't want to have children.

Yes by grandparents and siblings.

by anyone with children.

See also: Idiocracy https://www.youtube.com/watch?v=hL1-340ODCM