The twin boom can be explained by changes in when and how women are getting pregnant. Demographers have in recent years described a "delayer boom," in which birth rates have risen among the sort of women—college-educated—who tend to put off starting a family into their mid-30s or beyond. There are now more in this group than ever before: In 1980, just 12.8 percent of women had attained a bachelor's degree or higher; by 2010, that number had almost tripled, to 37 percent. And women in their mid-30s have multiple births at a higher rate than younger women. A mother who is 35, for example, is four times more likely than a mother who is 20 to give birth to twins...More at the Salon article. Image via.
...it turns out that black mothers are more likely to have twins than those of any other racial group. It has been known for decades that levels of FSH production differ among subpopulations in the U.S. and overseas. Black women in African countries produce more FSH than anyone else, and they have the highest fraternal twinning rate in the world. Women in East Asian countries, on the other hand, have the lowest FSH-levels and produce few twins.
25 August 2011
The twin rate in the U.S. has skyrocketed