"Assuming there is any genetic component to the desire for having children and religiosity (and I believe there is)"

The genetic argument should cancel itself it out. After all, if genetic factors should eventually cause people to have more children, then how is it possible for us to have a 55 year trend toward less children (as the article says, since 1957)? If genetics can eventually correct this trend, then why hasn't it already done so? For you to make this argument solidly, you'd have to establish at least 1 of 2 dependent arguments:

1.) there is some critical number that triggers a reaction

2.) there was, in the past, some force that allowed people to defy the genetic impulse to have children, but whatever that force was, it will no longer have as much power in the future

Here on Hacker News I have, several times, seen people invoke the idea that child-raising is a genetic impulse and that therefore the trend toward less children should be self-correcting. The people who advance this idea don't seem to get the irony of the suggestion.

Here is a bit of personal history: my great grandmother had 16 children. My mother had 4 children. Of the 4 of us, we are mostly past the age where we would consider having children. The 4 of us have so far had a total of 3 children, and I don't think there will be any more children, so my mom has less grand-children then she had children. This surprises her.

There are some powerful forces pushing the trend towards less children. My feeling is that some people are glib in their dismissals of the trend. A poorly thought out genetic argument would fall into my category of glib.

Agreed. You could easily argue that in an agrarian society children are an economic benefit (because your wealth is based on working the land), whereas in an urban society having children is an economic burden.

> If genetics can eventually correct this trend, then why hasn't it already done so?

Is this a joke? Evolution takes many generations. It has been less than 3 generations since 1957.

The question then becomes whether evolution has any pre-existing raw material to work with. The data give a resounding yes. Attention deficit hyperactuvity disorder is almost certainly genetic, and is strongly correlated with early reproduction and more children. Ditto for IQ.

And societies are also subject to cultural evolution. Catholicism and Mormonism confer a high fertility rate, and it appears to be heritable.

I wonder if this is one of the major ways (other than conversion) that the major religions of the modern world spread in the first place. After all, they all seem to emphasize having children to a great degree, something that I don't think existed in many other religions.

I've read somewhere before that the religious compulsion towards having many children is to keep the meme of religion going through multiple generations. It's certainly highly prevalent through the Catholic Church, especially given that the priesthood is essentially a non-replenishing rank based off the old tradition of following in your fathers footsteps for work.

I view religion in terms of evolution and natural selection. A religion which favors converting others will become more widespread than a religion that doesn't emphasize this, the same goes for emphasizing having many children.

...except for the fact that non-religiosity is spreading quite a lot faster than people can breed. Religious indoctrination runs in families, but reason and skepticism are universal.

I wouldn't count on it. Even if it were possible the genetic pool is too vast for single traits to really have an impact. Plus consider that most (if not all?) homosexuals have heterosexual parents - that is more influenced by number children, but it shows that there is more involved than just people who have the traits being selected out. Most of the biggest advocates against religion were born in religious families. Most parents regret having kids, most couples who have kids are less happy than couples who don't have kids. People wanting to be child free is here to stay and it will grow before it has any chance of being bred out. Choosing to be child free is the rational thing to do if you want to be happy. I welcome people to join more people avoiding having kids here: http://reddit.com/r/childfree

In case of homosexuality it could be that the genes which cause this in a man are also helping his sister in becoming more attractive to other men (and the brother of a homosexual woman to be more attractive to other women).

I have no stats on this, but it would be interesting to see if the sisters of gay men and the brothers of lesbian women do have more kids than the average (for the same education and income levels, of course).

There is a Italian study that shows mothers of gay men are quite a bit more likely to bear many children than mothers of only hetero children.

Their conclusion is there at least a partial genetic component, likely coding for "Likes to have sex with men" that the gay men just happen to get as a side effect of the very effective gene for women.