Sorry, Jonah, missed that one till someone pointed it out. Things get blurry and confused at this time of year.
“A study of 2,000 US college girls published in the American Journal of Human Biology in July 2006 shows that daughters who grow up without their fathers tend to have their first period earlier than those who blossom under their dad’s wing.”
Well, same answer as always to these things: What’s the methodology? Without knowing that, you can’t judge the value of the study.
The relevant meta-fact here is that much of the time–more often than not, in fact!–the methodology in these dev-psych studies stinks. Whether it stinks in this particular case, I have no idea, since I haven’t read the study, and have no time to do so right now.
The kind of thing that might be wrong with it is: Not correcting for race. Age of menarche is distributed differently for different races–that is a very well-established fact. So is number of biological parents in the household. So it might be–again I emphasize that without looking at the methodology I don’t know, I’m only saying that this kind of thing happens a lot with these studies–that black girls (early mean age of menarche, high proportion of fatherlessness) account for the entire effect.
Why is there so much stinky methodology in this field? Well, the previous paragraph tells you. It’s important for researchers to take account of race and heritability when doing these studies. If you believe the PC dogmas that THERE IS NO SUCH THING AS RACE! and that heritability is inconsequential by comparison with home-environment effects, then your study won’t be worth a damn, because both those beliefs are false. A surprising number of dev-psych researchers do believe them none the less, and so their studies aren’t worth a damn.
Again again, whether this particular study falls into that category I don’t know, and can’t budget the time to find out; but taking dev-psych literature as a whole, the probability is depressingly high.
If any expert in the field has looked at the AJHB study and is willing to be quoted, please email myself or Jonah.