There has been an increase in the number of couples turning to artificial insemination or in-vitro fertilization after marrying later. This has led to a surge in the number of twins.
According to Statistics Korea, the birthrate of twins and triplets increased from 1.8 percent in 2001 to 2.42 percent in 2006 and 2.94 percent in 2011, with the number up 39 percent from 9,966 to 13,852 over the same period.
The odds of conceiving twins naturally are a mere 0.43 percent.
The increase in twin births is directly proportional to the increasing age of Korean couples. According to Statistics Korea, the average marriage age of Korean women rose from 26.78 in 2001 to 29.14 in 2011, and the average age when they gave birth to their first child from 29.26 to 31.44.
In-vitro fertilization involves several eggs being fertilized, which increases the chances of having twins. Among the twins conceived at Cheil General Hospital in 2011, only 37.2 percent resulted from natural childbirth or in-vitro fertilization.
A rise in the number of twins is commonly seen in advanced countries that boast sophisticated medical technology and where people increasingly tend to marry later in life. According to the U.S. Centers for Disease Control and Prevention, the birthrate for twins and triplets there rose from 1.89 percent in 1980 to 3.31 percent in 2010.