By ERIN ALLDAY, San Francisco Chronicle

SAN FRANCISCO - Like alcohol and tobacco, sugar is a toxic, addictive substance that should be highly regulated with taxes, laws on where and to whom it can be advertised, and even age-restricted sales, a team of scientists contends.

Morgellons disease -- a creepy illness that leaves patients with painful lesions, gives them a feeling that bugs are crawling all over their body, and has them seeing colorful, threadlike fibers poking through their skin -- isn't infectious and probably isn't caused by anything in the environment, according to the first government study of the condition.

SAN FRANCISCO - It's no big secret that alcohol makes most people feel pretty good, but scientists have for the first time found evidence that liquor triggers the release of pleasure-inducing endorphins in the brain -- and that heavy drinkers are especially influenced by those endorphins.

The flu season hasn't kicked in yet, but infectious disease experts are on the alert for new strains of the virus, including another swine flu that's popped up in parts of the United States and a drug-resistant flu circulating in the Southern Hemisphere.

It sounds like science fiction, but scientists around the world are getting tantalizingly close to building the mind-controlled prosthetic arms, computer cursors and mechanical wheelchairs of the future.

SAN FRANCISCO - Last month Trent Arsenault got three women pregnant -- a new record for the Fremont man and father of 14 (and counting).

"I know the holidays are busy," Arsenault, 36, said with a chuckle, "but I didn't know that included babies."

Arsenault's been a sperm donor for five years, offering his semen to women he meets on the Internet for free.

The "bible" of American psychiatry -- a manual of mental health used around the world by doctors, consumers and insurance providers -- has come under fire from a growing group of psychologists who worry that proposed revisions will feed into a culture of overdiagnosing, and overtreating, otherwise healthy people.

For the first time in 30 years, the number of overweight schoolchildren in California is falling, suggesting that the state may finally be making some headway in the long battle to prevent childhood obesity, according to a report released Wednesday. But it's hardly time to start celebrating, public health officials said.

Grace Rego's spine curves so sharply that its "S" shape is obvious beneath her skin. But you'd never know it to watch the 4-year-old clamber over a sofa or chase her little brother around the family's home in Piedmont, Calif.

"The first thing her doctor said when he saw her back was, 'Whoa, I'm really sorry about this,' " said Grace's mom, Jennifer Rego.

SAN FRANCISCO - Nearly half of babies younger than 2 in the United States watch an average of two hours of TV every day, and 10 percent of children that age have used a smartphone, tablet or other mobile device at least once in their young lives, according to a survey released Tuesday.