“At birth, the sex ratio in the U.S. has historically been 105 men for every 100

–“At birth, the sex ratio in the U.S. has historically been 105 men for every 100 women. The ratio inverts around age 30. Since the mortality rate is higher for men than it is for women at almost every age group. That ratio decreases with age, until at age 90 or above there are…