What age is considered "middle age"?

As of 2014, there is not an agreed upon age range for middle age, but age ranges commonly used are 45 to 65 and 40 to 60. Middle age encompasses the two age categories between 35 and 54 on the U.S. Census.

Middle-aged adults can develop gray hair. Physical fitness tends to deteriorate, and weight gain is common. Everyone is affected differently by aging. Fertility decreases in men and women. Menopause occurs in most women when they reach their mid-40s or early 50s. Children born to middle-aged parents have an increased risk of certain disorders. The risk of miscarriage is also higher.