entral China's Henan Province will enhance a 2006 ban on ultrasound service used to determine the sex of unborn children as they vow to fight an expanding gender gap.

With a population of more than 106 million, Henan is the most populous province in the country. In 2012, there were 117.77 boys born to every 100 girls and with a ratio of 116.54 in 2013, according to statistics from the sixth national census.

A normal sex ratio is defined as anywhere between 103 to 107 boys born for every 100 girls.

In an effort to close the gap, the provincial government pledged to lower the sex ratio to 113.36, the target set by the central government for the province, by the end of 2015.

Serious gender imbalances occurred after the late 1980s when B-ultrasound technologies used for sex-selection were widely available in China. As a result, Chinese couples chose to abort female fetuses following the test, opting for boys to carry forward the family bloodline.

Although sex-selection for non-medical purposes has been banned in the province since 2006, the sex ratio has not been strongly affected.

Stricter policies will be implemented, the provincial government said. Married couples who want to have a second child will have to sign a contract with local family planning department to guarantee that they will not abort the fetus for non-medical purposes. They will be deprived of the opportunity to have a second child if they violate the terms.

Meanwhile, abortions will be conducted with stricter conditions and the purchase of B-ultrasound machines will be under government supervision. Endi