An increasing number of men are being treated for infertility. According to the Health Insurance Review and Assessment Service on Sunday, the number of men treated for infertility rose 51 percent from 23,099 in 2006 to 34,811 last year.

Ju Tae-seo, a urologist at Cheil General Hospital, said, "In the past, it was women who first came to the hospital for infertility checks, and men came only when it was confirmed that there was no problem with the women. But nowadays both husband and wife visit hospital together."

More women are being treated for infertility as well, from 120,000 five years ago to 150,000 in 2010, up 5.8 percent per year. Doctors say the increasing age of women at marriage is one of the main reasons. The average age of women at first marriage has risen from 26.5 in 2000 to 28.9 in 2010. Men are now marrying at the average of 31.8.

And couples where the wife is older than husband are becoming more common. Biologically, men’s reproductive ability does not fade until they middle age, but the quality and number of female eggs drop considerably with age, thus reducing the chances of natural pregnancy.

Even if older women are lucky enough to get pregnant, they face a greater risk of miscarriage. Over 90 percent of the women currently being treated for infertility are over 30, and there are 70,000 natural miscarriages a year.

Women are advised to get pregnant before the age of 35 to minimize the risk of infertility. Men should try to avoid stress, which reduces sperm activity, as well as smoking and drinking. Jun Woon-chun at the Health Insurance Review and Assessment Service said, "Most of the couples being treated for infertility are not completely infertile but have greatly reduced capacity for impregnation."