People diagnosed with a particular type of thyroid cancer and aggressively treated for it actually didn't have cancer after all. That's the conclusion of 24 endocrinology pathologists from seven countries who came together to reconsider the diagnosis and treatment of encapsulated follicular variant of papillary thyroid carcinoma.

The panel reviewed tumor-cell samples and did an exhaustive review of the medical literature, among other efforts, before concluding that the condition was precancerous but not cancer itself. The panel determined that the precancerous nodule that causes a lump in the neck rarely recurs or leads to complications once removed, with no further treatment necessary.

How your DNA affects your sex life

Your DNA doesn't determine when you lose your virginity, but it may play a larger role in the matter than scientists had thought.

A study identifies 38 specific places in the human genome that appear to be associated with the age at which people first had sex. These spots affect a range of genes, including some that seem to affect the timing of puberty and others that have been linked with risk-taking behavior.

"While social and cultural factors are clearly relevant, we show that age at first sexual intercourse is also influenced by genes," said John Perry, a researcher at the University of Cambridge.

Cleaner air, fewer lung problems

Air quality regulations in Southern California have led to large reductions in air pollution over the past two decades. A study reports that the cleaner air has been accompanied by a significant decrease in childhood lung problems.

The study, in JAMA, followed 4,602 children in Southern California and used data on ozone, nitrogen dioxide and particulate matter for each year. Parents also provided regular updates about symptoms like coughing and phlegm production in their children.

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