Why old men shouldn't impregnate young women.

Science, technology, and life.
April 28 2006 9:10 AM

Predators and Preemies

Why old men shouldn't impregnate young women.

(For the latest Human Nature columns on polygamy, obesity, and birth control, click here.)

Older men are more likely to produce premature babies. For a mother 20 to 24 years old, the risk of bearing a child before 32 weeks' gestation almost doubles if the father is 45 to 49 years old rather than 25 to 29. The younger the mother, the stronger the effect. Previous studies have linked older fathers to some pregnancy complications, birth defects, and diseases in offspring. Interpretations: 1) Men may accumulate bad mutations as they age or are exposed to toxins. 2) Nature may discourage big age differences between parents because they're disadvantageous to the child. 3) For God's sake, she's young enough to be your daughter. (For Human Nature's take on polygamy, click here. For incest, click here. For cousin marriage, click here.)

William Saletan William Saletan

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

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Men in southern Africa are lining up for circumcision. Doctors can't keep up with demand. Studies indicate it can cut by two-thirds your risk of getting HIV and can lower by 30 percent your risk of giving HIV to your partner. Critics' concerns: 1) Banging lots of partners is the big HIV risk factor, and men who get circumcised may feel free to do more of that. 2) Some men in line are getting circumcised because they think it'll make sex more enjoyable, so their cosmetic surgery is delaying another guy's life-saving surgery. 3) Medicine men are getting into the act, and "every year, the authorities in Eastern Cape Province in South Africa report deaths and amputations from botched circumcisions of young boys." (For Human Nature's previous update on adult circumcision, click here. For bloodsucking circumcision, click here.)

American obesity is up to 50 percent more prevalent than previously reported. A review of data indicates that from 1988 to 2002, male obesity rose from 16 to 29 percent, and female obesity rose from 22 to 35 percent. And that's not even counting all the overweight people. Least-obese states as of 2000: Colorado (18 percent of men and 24 percent of women) and Montana (21 percent men and 16 percent of women). How did we screw up the initial estimates? By interviewing people on the phone. Women lied about their weight; men lied about their height. (For Human Nature's take on junk food and the war on fat, click here.)

The risk of addiction to heroin and morphine is "genetically influenced." A study of families shows chromosome regions that correlate with opiate dependence. The next step is to hunt in these regions for key genes. Authors' conclusions: 1) Addiction involves more than willpower. 2) Once we identify the genes, we can warn and watch people at risk of addiction. 3) Once we know how the genes work, we can design drugs to block them. (For Human Nature's update on the role of genes in marijuana-related psychotic disorders, click here. For addiction to tanning, click here. For pills that control compulsive gambling, click here.)

Tanning salons are targeting high schools. A study of Denver-area schools found that 11 of 23 put tanning ads in their newspapers; 18 salons placed the ads: nearly 40 percent of the ads offering unlimited tanning; and only two ads mentioned parental involvement. Authors' conclusions: 1) According to the World Health Organization, ultraviolet radiation from tanning beds or sunlamps is a likely carcinogen. 2) It's being "specifically marketed to adolescents." 3) This is why more young women are getting skin cancer. 4) Studies suggest tanning can be addictive. 5) Schools and legislatures should ban tanning ads to minors, just like cigarette ads. (For updates on tanning addiction and regulation, click here and here. For Human Nature's take on the shift from regulating tobacco to regulating junk food, click here)

The military is developing "Brain Ports" to enable soldiers to see with their tongues. The idea is to route audio or video signals (from a helmet-mounted camera, for example) through microelectrodes in the tongue so your brain receives these extra images without distracting your eyes, ears, or hands from immediate tasks. "In testing, blind people found doorways, noticed people walking in front of them and caught balls." Applications: Rear vision, night vision, sonar. The navy will watch the technology in action next month and consider whether to fast-track it so it's operational by the end of the year. (For David Plotz's takes on artificially enhanced vision and hearing, click here and here.)

Men who deny paternity are wrong 70 percent of the time. On the other hand, men rarely err the other way: Previous estimates said 10 percent of men who thought they were fathers of certain children were mistaken, but a new analysis of paternity tests  indicates only 2 percent to 4 percent are actually mistaken. The percentage of men who think they're dads but aren't ranged from half a percent among some Jews to nearly 12 percent in parts of Mexico. The good news: We're not fools. The bad news: We're cads.

The Vatican is considering whether to condone condoms as AIDS prevention. The church opposes condoms as contraception and thinks promoting them to stop AIDS is counterproductive because it encourages promiscuity. But a leading moderate cardinal says the church should allow condoms within marriage when one spouse has HIV, and the pope has asked his health department to consider whether this might be acceptable as a lesser evil.

The FDA said "no sound scientific studies" support medical marijuana. FDA's arguments: 1) We're the ones who decide what's safe and effective. 2) States are politicizing science by legalizing medical pot without going through us. 3) Our favorite study says pot isn't medically effective. Critics' arguments: 1) Well, our favorite study says it is. 2) The FDA is politicizing science by ignoring our study in order to justify the Bush administration's moral position against pot. 3) The real purpose of the FDA statement is to cow state legislators into voting down medical pot bills. Consensus: The feds are warning you that they can bust you, even if your state says it's legal. (For Human Nature's previous update on pot legalization, click here.)

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