Discovered: No sign of a gay gene, but homosexuality could start in the womb; childhood obesity is going down; that fish you're eating probably isn't really fish; a new SARS to freak out about.

Homosexuality isn't genetic after all. But don't start saying this proves it's a "lifestyle choice," fundamentalists. Researchers from UC Santa Barbara and Uppsala University found a biological basis for same-sex attraction, locating the origins of homosexuality in the womb. Epi-marks, the genetic switches that regulate how our genes express themselves, can be passed down from mother to son or father to daughter while the fetuses gestate, the researchers found, adding that certain "sexually antagonistic" epi-marks may also be involved. [io9]

Kids are slimming down. Well, with 17 percent of them obese, could they really get that much rounder? Researchers across the country are noticing that children in cities like New York, Los Angeles, and Philadelphia are on average getting less overweight. The margins aren't huge, but they reverse a long troubling trend. "It’s been nothing but bad news for 30 years, so the fact that we have any good news is a big story," says New York City health commissioner Dr. Thomas Farley. The scientists—being skeptical, as is their wont—can't attribute the decline to any specific factors yet, but there are mumblings about Michelle Obama's emphasis on healthy eating and the recent elimination of deep friers from school cafeterias. [The New York Times]

Fish is usually fake in New York. Think that maguro sashimi you had in New York recently was just to die for? Will, we hate to break it to you, but it was probably not high-end raw tuna, but escolar, a downmarket substitue that causes gastrointestinal problems. Ocean protection group Oceana released a study that claims three in five seafood retail outlets in New York—from sushi restaurants to grocery stores—are mislabeling fish. "We have a very complex and murky seafood chain with no traceability," says Oceana's senior scientist Kimberly Warner, who chalks up the problem to lacking regulation. "If there were more enforcement on the ground as opposed to more regulations on the books, we think we'd be seeing less fraud," says Gavin Gibbons of the National Fisheries Institute. [NPR]

SARS: The Sequel. Remember 2002, when a mysterious virus had people throughout the world wearing surgical masks and warily maintaining five feet between themselves and anyone coughing in public? Well, a virus closely related to the one that caused SARS is back on the scene, according to researchers from the Erasmus Medical Center. The first victim of this new pathogen—which bears the snappy name hCoV-EMC—was a 60-year-old Saudia Arabian man who died from severe pneumonia this spring. Since then, nine people have been infected and five have died. Like SARS, hCoV-EMC comes from the coronavirus family. Researchers believe it could also infect bats and pigs. "The fact that [hCoV-EMC] can infect bat cells is consistent with the hypothesis that bats might be the origin of this virus, but this finding doesn't prove it," says Emory University epidemiologist Larry Anderson. "This virus had to come from an animal source—there's no other explanation for what's going on. But we still don't know what that source is."  [Science Now]