Adding to the anxiety is the fact that we know so little about how early puberty works. A few researchers, including Robert Lustig, of Benioff Children’s Hospital, are beginning to wonder if many of those girls with early breast growth are in puberty at all. Lustig is a man prone to big, inflammatory ideas. (He believes that sugar is a poison, as he has argued in this magazine.) To make the case that some girls with early breast growth may not be in puberty, he starts with basic science. True puberty starts in the brain, he explains, with the production of gonadotropin-releasing hormone, or GnRH. “There is no puberty without GnRH,” Lustig told me. GnRH is like the ball that rolls down the ramp that knocks over the book that flips the stereo switch. Specifically, GnRH trips the pituitary, which signals the ovaries. The ovaries then produce estrogen, and the estrogen causes the breasts to grow. But as Lustig points out, the estrogen that is causing that growth in young girls may have a different origin. It may come from the girls’ fat tissue (postmenopausal women produce estrogen in their fat tissue) or from an environmental source. “And if that estrogen didn’t start with GnRH, it’s not puberty, end of story,” Lustig says. “Breast development doesn’t automatically mean early puberty. It might, but it doesn’t have to.” Don’t even get him started on the relationship between pubic-hair growth and puberty. “Any paper linking pubic hair with early puberty is garbage. Gar-bage. Pubic hair just means androgens, or male hormones. The first sign of puberty in girls is estrogen. Androgen is not even on the menu.”

Frank Biro, lead author of the August 2010 Pediatrics paper and director of adolescent medicine at Cincinnati Children’s Hospital, began having similar suspicions last spring after he flew to Denmark to give a lecture. Following his talk, Biro looked over the published data on puberty of his colleague Anders Juul. In Juul’s study, some of the girls with early breast development had unexpectedly low levels of estradiol, the predominant form of estrogen in women’s bodies from the onset of puberty through menopause. Biro had seen a pattern like this in his data, suggesting to him that the early breast growth might be coming from nonovarian estrogens. That is to say, the headwaters for the pubertal changes might not be in the girls’ brains. He is now running models on his own data to see if he can determine where the nonovarian estrogens are coming from.

The possibility that these early “normal” girls are reacting to estrogens that are not coming from their ovaries is compelling. Part of the comfort is that a girl who is not yet in puberty may not have developed an adolescent brain. This means she would not yet feel the acute tug of her own sexual urges. She would not seek thrills and risk. Still, the idea that there are enough toxins or fat cells in a child’s body to cause breast development is hardly consoling. Besides, some of the psychosocial problems of early puberty derive from what’s happening inside a girl’s body; others, from how people react to her. “If a girl is 10 and she looks 15, it doesn’t make any difference if her pituitary is turned on or if something else caused her breast growth,” Biro says. “She looks like a middle adolescent. People are going to treat her that way. Maybe she’s not interested in reciprocal sex, but she might be pressured into sex nonetheless, and her social skills will be those of a 10-year-old.”

So what are families of early bloomers to do? Doctors urge parents to focus on their daughters’ emotional and physical health rather than on stopping or slowing development. In this way, the concept of a new normal is not just a brushoff but an encouragement to support a girl who is vulnerable.

“I know they can’t change the fact that their daughter started developing early, but they can change what happens downstream,” Louise Greenspan, the pediatric endocrinologist at Kaiser Permanente, told me. Parents can keep their daughters active and at healthy body weights. They can treat them the age they are, not the age they look. They can defend against a culture that sells push-up bikinis for 7-year-olds and otherwise sexualizes young girls. “Most of the psychological issues associated with early puberty are related to risk-taking behaviors,” Greenspan continued, and parents can mitigate those. “I know it sounds corny and old-fashioned, but if you’re in a supportive family environment, where you are eating family meals and reading books together, you actually do have control.” Early breast growth may be just that — early breast growth: disconcerting, poorly understood, but not a guarantee of our worst fears. “You don’t go directly from the first signs of early puberty to anorexia, depression, drinking and early sexual debut.”

In Fort Collins, Tracee, Ainsley’s mother, tried to stay focused on the positive. At one point during my visit, she disappeared into her basement, the headquarters for her company, T.G.R. Body, and returned with a pink hat box filled with chemical-free samples of Peppermint Pimple Popper and Bad Hair Day Miracle Powder. “I just want to be part of the solution,” Tracee said, rubbing a sample of silver hair-streaking gel on my wrist. “I’m so tired of running away. I need to have something Ainsley is moving toward.”

Mothers who have been through it urge candor. “Be honest with her, and by honest I mean brutally honest” — about what’s going to happen to her body — “while still being kind ,” says the mother of a girl who recently turned 10 but who first showed signs of developing what she calls “a shape” at age 3. “You don’t want your daughter experiencing something for which she’s unprepared.”

Patience and perspective may be the greatest palliatives. “The thing with puberty is that everybody is going to go through it at some point,” another mother told me. Three years ago this woman was installing small trash cans in her third-grade girl’s school bathroom stalls so that her daughter could discreetly throw away menstrual pads. But now that daughter is 12, in the sixth grade; her body seems less strange. “I feel so much better, and so does she. By another two or three years down the road, all the other girls will have caught up.”