Some clues have indicated that female brains may stave off aging better than male brains, such as better cognitive ability later in life and longer life expectancies. However, the reason behind these observations remains a mystery. Scientists at the Washington University in St. Louis have applied machine learning to uncover yet another clue in the slowly developing picture of sex difference in the brain - that male brains appear older than their female counterparts of the same physical age. Charlie brings in the paper that has scientists scratching their heads and news outlets spinning. Read the paper and news articles here.