Wednesday, January 28, 2009

Interracial fertility: Over at 2blowhards, Gregory Cochran said in Monday's interview that:

Well, one usual claim is that individuals from every human population are fully interfertile, completely able to interbreed... Of course, like so many sweeping statements, no one has carefully tested this for all possible combinations.
It is true that research has not answered this question, but a recent study tell us that some combinations seem as fertile as same-race couplings. I can't access the full text, but here's some of the abstract:

This study uses 2000 - 2005 American Community Survey data on married (n =272,336) and cohabiting (n = 48,769) couples to compare the fertility of endogamous and exogamous couples. Interracial and interethnic partnering do not affect fertility for cohabiting, Black-White, Mexican-White, and Puerto Rican-White intermarried couples, but it does reduce fertility in Chinese-White and Asian Indian-White intermarriages (Fu, Vincent Kang. Journal of Marriage and Family, Volume 70, Number 3, August 2008 , pp. 783-795(13)).

13 comments:

Razib said...

but it does reduce fertility in Chinese-White and Asian Indian-White intermarriages

Whiter People. i know whereof i speak.

ironrailsironweights said...

but it does reduce fertility in Chinese-White and Asian Indian-White intermarriages

Does the study take age into account? Many Asian-White marriages seem to involve somewhat older men, e.g. the mail-order bride marriages, and men's sperm production declines with age.

Peter

Ron Guhname said...

Peter: I don't know. I'll let you know if I get my hands on the full text.

Anonymous said...

Wouldn't you assume that if there's a biological reason for low fertility in some inter-ethnic pairings, it would more likely to show up in black/non-black couples than in other crossings. The black/non-black split is older than any of these other splits, isn't it?

So it seems as if humans are fully inter-fertile (though we might want to look at Aborigines and Bushmen to make sure).

Statsquatch said...

We need a randomized experiment. Obama should make it part of his stimulus package. I volunteer.

Jason said...

Life is pretty flexible. It has to be, by definition, or it becomes non-life. We don't see what can't exist, so we should not be surprised when what does exist is good at existing and perpetuating itself despite obstacles. "Life... finds a way." There's even reasonable speculation that human/chimp crossovers are possible with little or no advanced genetic engineering. (Google "humanzee".) That may or may not be the case, but it puts interracial fertility into some perspective.

Blode032222 said...

I'm not sure what counts as fertility, actually. I believe chihuahua sperm can fertilize mastiff ova, but the little fella probably wouldn't be able to pull off the courtship thing. And I'll bet a chihuahua dam couldn't bring a clutch of chihuahua-mastiff pups to term. If there were no other dog breeds, I'm not sure you could treat them as a single species: human intervention is the only way for them to interbreed.

ironrailsironweights said...

So it seems as if humans are fully inter-fertile (though we might want to look at Aborigines and Bushmen to make sure).

Dunno about the Bushmen, but Australia has plenty of part-Aboriginals. They might even outnumber full-bloods.

Peter

Jason Malloy said...

What happens when a mastiff impregnates a chihuahua?

Does the little ratdog swell up like Violet Beauregarde and explode like a pigeon plumped out on wedding rice?

The two breeds look really different, but at the genetic level they are like siblings. Nevertheless some physiological differences might just necessarily lead to spontaneous abortion.

I don't know what happens when a Dutch ogre rawdogs a fertile young Pygmy, but I hope she wouldn't become Ms. Creosote.

Jason Malloy said...

I'd like to know the control group in the cited study, btw.

Are Chinese-White mixes less fertile than both W-W and C-C pairings? Because East Asians have lower fertility. East Asian sperm, in particular, is genetically worse. (and lower estrogen, etc, in the females would reduce fertility as well)

Monogamous populations don't need reproductive systems all geared up for fuckwarring.

Razib said...

Are Chinese-White mixes less fertile than both W-W and C-C pairings? Because East Asians have lower fertility. East Asian sperm, in particular, is genetically worse. (and lower estrogen, etc, in the females would reduce fertility as well)

i really doubt that this matters much. it isn't like you need to keep fucking someone after you impregnate them. old dudes with crappy sperm can have plenty of kids if they want to usually.

Jason Malloy said...

Just throwing it out there -- I suspect fertility quality does play a role in family size but can't say how much. I do agree with you though that A-W couples are exactly the kind of educated, upper-class folks who have smaller families.

Contrablue said...

Are their data adjusted to control the confounding variable of IQ?

Fertility is not merely a matter of viability of germ plasm -- it's a matter of willingness to procreate.