Girls around the country are starting puberty ever younger, says a new study out in Pediatrics.

Researchers led by Frank Biro studied more than a thousand girls between six and eight years old from New York, Cincinnati, and San Francisco. Their findings: By the age of 7, about 23 percent of black girls, 15 percent of Hispanic girls, and 11 percent of white girls showed enough breast development to be considered pubescent. Those numbers are even more extreme than the findings of a similar 1997 study that seemed to show the age entering puberty was dropping fast.

Says Biro:

“In 1997, people said, ‘That can’t be right; there must be something wrong with the study’. But the average age is going down even further” [Los Angeles Times].

The starkness of Biro’s statistics has drawn plenty of attention. But just what it means is a difficult question, because there’s no “ideal” age for entering puberty.

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Does your first- or second-grade daughter have trouble with math? Her anxiety could be stemming not just from a genuine fear of number crunching but also, a new study indicates, from an anxious female math teacher.

The study (pdf) published in the Proceedings of the National Academy of Sciences shows that if a female teacher is anxious about math, she tends to pass on that anxiety to her female students. This can make the female students believe they aren’t hard-wired for math like the boys, and cause them to shy away from fully flexing and developing their mathematical muscles.

The findings are the product of a year-long study on 17 first-and second-grade teachers and 52 boys and 65 girls who were their students [Science Daily]. Researchers recruited the female teachers from a Midwestern school district and assessed their level of math anxiety. They also gave math tests to 117 of these teachers’ students and jotted down their beliefs about math and gender at the beginning and end of the year. By the end of the year, the more anxious teachers were about their own math skills, the more likely their female students – but not the boys – were to agree that “boys are good at math and girls are good at reading” [AP].

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