Chinanews, Beijing, July 19 - Though China has successfully controlled its population explosion nowadays, the new problem of severely imbalanced sex ratio has started to haunt the country. It is estimated that there will be about 37 million more men of marriageable age than women by 2020. That is to say, about 10% of men will not be able to find wives by then.According to the national census in 2005, the sex ratio of newborns in China was 118.88:100, while the normal figure should be 104:100 - 107:100. China has witnessed imbalanced sex ratio since the 1980s. Now it has become the country with the severest sex imbalance in the world.Experts believe that the traditional prejudice against women in China has contributed to the sex imbalance, as many parents depend upon B-Ultrasonic make sure that they have male babies. Though the government has issued regulations to ban unnecessary fetus gender identification, some doctors still offer such service.