Gestating body parts for transplantation.

Gestating body parts for transplantation.

Gestating body parts for transplantation.

Science, technology, and life.
Feb. 8 2008 9:01 AM

Jawbone of an Ass

Gestating body parts for transplantation.

New column 2/6 on Obama and the white vote. (For discussions of the latest topics, check out the Human Nature Fray.)

The difference between fat and nonfat kids is 77 percent genetic. Sample: 10,000 British twins aged 8 to 11. Results: Differences in fat were driven largely by genetic differences, not by differences in family environment. Fatalistic attitude: Differences in obesity are genetic, so there's nothing you can do about it. Moralistic attitude: Changes in behavior, not in genes, have caused the obesity epidemic. Therefore, being fat or having a fat kid is your fault. New attitude: Differences in obesity are genetic, but changes in behavior, not in genes, have caused the obesity epidemic. Therefore, being fat or having a fat kid isn't your fault in particular, but there's a lot we can and should do about it. (Related: Human Nature's takes on obesity, personal responsibility, and social responsibility.)

William Saletan William Saletan

Will Saletan writes about politics, science, technology, and other stuff for Slate. He’s the author of Bearing Right.


A man grew his own jaw transplant in his abdomen. Scientists attached his stem cells to a scaffold and "put it inside the patient's abdomen to grow for nine months." The cells "turned into a variety of tissues and even produced blood vessels." Surgeons then transplanted the tissue to his head. Benefits: 1) No animal viruses, since doctors didn't use animal tissue. 2) No rejection problems, since the transplant matches the patient's DNA. 3) Fast recovery, since the new bone was grown instead of taken from his leg. Approved reaction: This brings "custom-made living spare parts for humans a step closer to reality." Unapproved reactions: 1) Congratulations—it's a bone! 2) Is that a bone in your abdomen, or are you just glad to see me? (Related: Regrowing lost body parts—or gestating them in embryos.)

Male circumcision failed to reduce HIV infection of female sex partners in a study. Previous studies showed circumcision could reduce infection of the circumcised men. New findings: 1) Circumcision didn't reduce the rate of transmission from infected men. 2) It actually increased the rate, because some couples resumed sex before the wound had healed, despite receiving free condoms and having been counseled to wait. Caveats: 1) The study was small, and the differences weren't statistically significant. 2) Circumcision did lower the rate of herpes in men. 3) The study doesn't change the fact that if circumcision keeps the man uninfected, it keeps his partner uninfected, too. Authors' conclusion: Let's figure out how to get people to abstain till the wound is healed. Human Nature's view: Good luck with that. (Related:  The case for genital mutilation.)

Scientists made human embryos from three parents. Recipe: 1) Make a regular IVF zygote. 2) Remove the nucleus from a second woman's egg. 3) Remove the zygote nucleus and put it in the egg. Result: The embryo develops using the first woman's nuclear DNA and the second woman's mitochondrial DNA. Purpose: Avoid diseases from the first woman's mitochondrial DNA. Objections: 1) It's unnatural. 2) The scientists destroyed all the embryos. Scientists' rebuttals: 1) "We are not trying to alter genes, we're just trying to swap a small proportion of the bad ones for some good ones." 2) "Most of the genes that make you who you are are inside the nucleus. We're not going anywhere near that." Human Nature's bet: These rebuttals, which make sense in the case of mitochondria, will soon be extended to justify changes in nuclear DNA. (Related: HN's previous update on three-parent embryos.)

A Mississippi lawmaker proposed to ban restaurants from serving fat people. Bill text: 1) Restaurants "shall not be allowed to serve food to any person who is obese." 2) "The State Department of Health shall monitor [compliance] and may revoke the permit of any food establishment that repeatedly violates" this rule. Rationales: 1) Mississippi has the nation's highest obesity rate. 2) "Mississippi's obesity rate cost Medicaid alone $221 million each year." Objections: 1) "The food police have gone too far." 2) "It's discriminatory." 3) The state should focus on promoting exercise instead. 4) "Some people are big and happy." 5) "I've seen a lot of crazy laws, but this one takes the cake. Literally." Sponsor's rebuttal: I'm just trying to highlight the problem. Human Nature's view: Banning people from restaurants based on appearance. In Mississippi. Great idea. (Related: The war on junk food; the war on trans fats; the war on soda; the war on salt.)

Fat people are less medically expensive than other people over a lifetime, according to a Dutch study. Findings: 1) Fat people cost more per year than smokers or nonfat nonsmokers do, but only up to age 56. 2) After that, smokers cost more. However, 3) fat people and smokers die earlier (by 4 and 7 years, respectively). Net result: "Lifetime health expenditure was highest among healthy-living people and lowest for smokers," with fat people in between. Conclusion: "Obesity prevention may be an important and cost-effective way of improving public health, but it is not a cure for increasing health expenditures." Critiques: 1) The study didn't include non-medical costs, such as lost productivity. 2) If saving money is our overriding goal, let's promote quick killers such as lung cancer. Old argument for the war on fat: Fat costs everyone money. New argument for the war on fat: Fat's costs are "immeasurable." (Related: Financial penalties for fat employees; obesity and responsibility; the war on smoking.)

As if losing the Super Bowl weren't bad enough: A senator threatened to hold congressional hearings on the NFL's destruction of evidence in the New England Patriots espionage case. Background: The NFL fined the Patriots for using a video camera to decipher an opponent's signals. The NFL then destroyed the videotapes. (The NFL and the Patriots deny a new allegation of an additional taping incident.) Suspicion: It's a cover-up. NFL commissioner's excuses: 1) We finished our investigation, so we didn't need the tapes anymore. 2) We were afraid somebody would leak them to the press. 3) We had to destroy them so that if some other tapes showed up, we'd know there were some other tapes. 4) The Patriots have been punished enough. 5) The tapes weren't from this season. 6) "It probably had limited, if any, effect on the outcome of games." 7) Taping is "done quite widely in sports, and teams prepare for that." 8) "In one of the tapes, a coach was waving at the cameras, showing that they knew they were being taped." Opposing players' take: 1) Taping, like steroids, is cheating. 2) But what really ticks us off is the Patriots' holding. Human Nature's question: If taping is as pervasive and inconsequential as the NFL says, why does the NFL prohibit it? (Discuss.)

Men are getting more oral cancer from sex. Data: 1) Oral cancers (in "the tonsils, lower tongue and upper throat") related to HPV "increased significantly" in men over the last 30 years. 2) In men, these cancers are now as common as oral cancers from alcohol and tobacco. 3) But in women, they've "declined significantly" during the same period. Researchers' conclusions: 1) "Changing sexual behaviors" are driving the trends. 2) Tobacco use is declining. Translations: 1) Smoking is going down. 2) Men going down is going up. 3) Women going down is going down. Dissenting view: Maybe people are getting these cancers from "unwashed hands," not oral sex. (Riiiiight …) Policy recommendations: 1) Maybe we should vaccinate boys, not just girls, against HPV. 2) Did we mention that HPV can cause penile and anal cancer? Related: 1) Oral sex and mouth cancer. 2) HPV and anal cancer. 3) Human Nature's take on the risks of oral vs. anal sex.

Latest Human Nature columns:  1) Obama and the white vote. 2) Bush, stem cells, and stubbornness. 3) Abortion and teen sex. 4) Why the polls botched New Hampshire. 5) The best Human Nature stories of 2007. 6) The top privacy threats of 2007. 7) Are cultural trends changing our genes? 8) The travesty of political robo-calls. 9) Are Jews genetically smart? 10) Rethinking the age of consent.