MercuryNews.com reports on a new study out of Stanford University which suggests that the older a man is when he marries, especially after age 40, the more likely it is that his bride will be significantly younger, regardless of whether or not the man is wealthy.

Co-investigators Paula England and Elizabeth McClintock have found that “men in their 40s tend to marry women who average seven years younger, men in their 50s are marrying brides who average 11 years younger, and men in their 60s are marrying women who are 13 years younger. ” 

England and McClintock suggest that this may be due to changes in family structure after the 1960s, but attribute this trend largely to what they call “a double-standard of aging” — where “the male idea of beauty is found in women in their early twenties and remains fixed as men age.”