When men outnumber women, females marry younger and the age gap between spouses grows, a University of Michigan study shows…

For example in Las Vegas, where there are six men for every five women, the median marrying age for men and women is 28.3 and 24.5, respectively. Contrast that with Birmingham, Ala., where there are 11 women for every 10 men, and the median marrying age for men and women is 26.9 and 26.7, respectively.

When the ratio of men to women is greatly out of balance, it creates social tension and encourages markets for services like sex trafficking and prostitution, Kruger said. When there is a surplus of men, there are likely higher rates of accidents and violence as men engage in riskier behavior to compete for women and resources. When there is a surplus of women, sexually transmitted disease can increase as women become more promiscuous.