Monogamy seems to have been doing pretty well.

Call me old-fashioned, but I'd rather see discrete dots than continuous lines - but I suppose you want jokes about 2.4 children.

This is only legal children for the men, not biological children. Paternity, remarriage, etc. may change the result in the context of actual fertility.

It is interesting to see what proportions of the population have various numbers of children. I was wondering if the following data is available:

--What percentage of the adult US population (say, between 25 and 65) has any children? I suppose one could take the area under the graph provided, but what would that work out to?

Also:

--What percentage of the adult US population is married?

If anyone knows where this information is available, I'd be greatly interested in hearing about it.

1) sda.berkeley.edu/cgi-bin/hsda?harcsda+gss06

2) census.gov

seek and you can receive.

At the survey site try

ROW: AGE
COLUMN: CHILDS
CONTROL: SEX
FILTER: RACE(1)

Run Table

and then repeat with RACE(0), RACE(2) and RACE(3)

Interesting...The textbooks say that men are more likely to have either a lot of children (Genghis Khan) or none, while women should have an intermediate number. Therefore, the male curve should be flatter. But the data shows that they are nearly the same! The only small problem with this study is that it probably simply asked people how many children they have. People can either lie, or in the case of men, be mistaken about paternity. Studies have shown that about 10% of the time, a man who thinks that he is the father of the child is mistaken. The real father is someone else (see The Sperm Wars by Robin Baker).

Chemdude, I was thinking the same thing about the male curve not being flat enough. I'm particularly suspect of the data at the child=1 level. So more women go childless than men? Really? I flat-out don't buy that. (at least in terms of biological children)

As for the Genghis Khans out there, they'd be in the long tail which excludes them from the graph.

I think the finding of non-paternity being 10% was based on some faulty data, if I remember correctly. I believe that data was based on blood-type studies which were flawed because it turns out there really are a lot of cases out there where babies are born with blood types that don't seem to follow the rules. (Usually because one of the parents has something wrong with one of their A or B alleles.)

It is rare, but if you're only looking at the subset of supposed non-paternity, it is significant.

paternity
http://www.gnxp.com/blog/2007/05...round- world.php

Mathematical studies (see http://www.theatlantic.com/doc/2...c/200205/olson) suggest that 20% of people in the middle ages failed to leave any descendants who survived to our time. This includes people who had children, but whose children failed to pass on their genes. That percentage appears to hold today as well. Evolution is still very much at work in sculpting our kind.

The current view is that NON PATERNITY EVENTS (Razib: NON ...) are quite rare in societies which are not in war. In the general Australian population (and most of Western society), misattributed paternity is around 1-5%, and usually much closer to 1% than 5%. This backs up a 2001 Australian sex survey that looked at 10,173 adults who had been in a regular relationship for over a year. This survey found that 2.9% of women had more than one sexual partner over that year.

Regarding the estimate that 20% of the men living some 500 years ago have no descendant, I think the number is much higher. Maybe in England, which was an exceptionally stable and ordered society, but not elsewhere. But even in England, almost all the family names mentioned in the Doomday Book are non-existent today. It is said that the population of the Middle Ages is not the same as we have today, and there was strong selection/evolution. This is a very active research area and it is worth following it.