As South Korea faces a falling marriage rate, a recent government study showed that the unmarried male population here outnumbers its female counterparts by nearly 20 percent.

According to the Korea Institute for Health and Social Affairs report released Monday, unmarried South Korean men outnumbered unmarried women by 19.6 percent in 2021, with the imbalance in gender ratio being more pronounced outside of metropolitan areas. The report used Statistics Korea data on those born between 1970, 1975, 1980, 1985, 1990, 1995 and 2000, defining them as those in the reproductive age.

The gender disparity among singles was most profound in North Gyeongsang Province, which had 34.9 percent more bachelors than bachelorettes, followed by 33.2 percent in South Gyeongsang Province, and 31.7 percent in North Chungcheong Province.

In contrast, Seoul had just 2.5 percent more unmarried men than unmarried women, leading all regions in terms of evenly distributed gender population among singles. The next on the list was Busan, which had 16.2 percent more single men than women.

The two cities -- the two most populated cities in the country accounting for roughly 24.7 percent of the entire population -- were the only regions with figures less than the nationwide average of 19.6 percent.

Researchers noted that the gender disparity among singles can be attributed to gender attitudes that persisted from the early 1980s up to 2006. Factors that contributed to such phenomenon are the nationwide preference for sons, faltering fertility rate, and technological advances that allowed parents to know the sex of the fetus, they said.

As a result, unmarried men began to greatly outnumber their female counterparts in the mid-2000s, which was when the people born in the early 1980s began to account for more of the unmarried population. The report showed that the marriage rate of men born during that time was far lower than that of women.

For example, as of 2020, 46.5 percent of the men born in 1985 were unmarried, which was far greater than 29.1 percent of women in that age group. This age group was close to the average age South Korean men got married in that year, which was 33.2.

South Korea has been seeing a continued decrease in the number of marriages in recent years, with the Korean Statistical Information Service data showing 193,673 marriages in 2023. This marked a 40 percent drop compared to 322,807 marriages in 2013.

"Considering the time the people born during the gender imbalance era will reach the reproductive age, (gender imbalance) is expected to affect the single-gender ratio for the time being," the researchers wrote.