Your Evil Twin
And other news from science and technology.
Latest Human Nature columns: 1) Why GPS tracking is good for felons. 2) No steroids in football, but let them eat steak. 3) Why pro-lifers fear the morning-after pill. 4) If steroids are cheating, why isn't LASIK? 5) Tom DeLay's mortal hypocrisy. 6) Terri Schiavo's persistent legislative state. 7) Jews vs. Catholics in the stem cell debate. 8) A plan to create an embryo-like thing. 9) The case for raising the retirement age. 10) What Larry Summers got right and wrong.
Gay men's brains react to pheromones the same way straight women's brains do. Some geneticists think gay men carry an attraction-to-men gene that has survived natural selection because it's reproductively advantageous in women. But the pheromone researchers say their study just shows correlation, not causation.
Most people are chimeras, according to DNA tests analyzed by a Mayo Clinic expert. A chimera has someone else's cells living in her body. In most cases, presumably, the other person is her mother. But it could be an absorbed twin: 20 percent to 30 percent of embryonic twin pairs end up as single births.
The mayor of Detroit wants to tax fast food. The tax would add 2 percent to the 6 percent meal tax and would include salads at fast-food restaurants.
States are banning Internet hunting, which lets users shoot real animals by remote control. Texas acted last month, California acted last week, and a ban in Virginia takes effect July 1.
Gay groups are challenging an FDA recommendation that sperm banks refuse donations from gay men. The groups argue that HIV screening solves any AIDS threat without requiring bias.
At the Kansas evolution hearings, witnesses for "intelligent design" conceded that the Earth is four billion years old. But they denied that humans shared primate ancestors. The lawyer for evolutionists emphasized that evolution-based curriculum doesn't preclude scientific debate or belief in God. (For Human Nature's take, click here.)
Mice genetically engineered to make a human antioxidant lived 20 percent longer. Scientists designed the mice to make extra catalase, an enzyme, in their mitochondria.
The risk of psychological harm from marijuana may be genetic. The U.S. Office of National Drug Control Policy cites two 2005 studies; one found that "one in four people may have a genetic profile that makes marijuana five times more likely to trigger psychotic disorders."
A common incision on women in labor is counterproductive. An analysis indicates routine episiotomy raises the risk of torn tissue, pain, stitches, and sexual discomfort.
Will Saletan covers science, technology, and politics for Slate and says a lot of things that get him in trouble.